kc3-lang/kc3

diff --git a/libc3/sequence.c b/libc3/sequence.c
index 2d02a0c..a50ea21 100644
--- a/libc3/sequence.c
+++ b/libc3/sequence.c
@@ -21,16 +21,20 @@ void sequence_clean (s_sequence *seq)
 
 s_sequence * sequence_init (s_sequence *seq, f64 duration,
                             const s8 *title, f_sequence load,
-                            f_sequence render, f_sequence unload)
+                            f_sequence render, f_sequence unload,
+                            void *window)
 {
+  s_sequence tmp = {0};
   assert(seq);
-  seq->dt = 0.0;
-  seq->t = 0.0;
-  seq->duration = duration;
-  seq->title = title;
-  seq->load = load;
-  seq->render = render;
-  seq->unload = unload;
-  tag_init_void(&seq->tag);
+  tmp.dt = 0.0;
+  tmp.t = 0.0;
+  tmp.duration = duration;
+  tag_init_void(&tmp.tag);
+  tmp.title = title;
+  tmp.load = load;
+  tmp.render = render;
+  tmp.unload = unload;
+  tmp.window = window;
+  *seq = tmp;
   return seq;
 }
diff --git a/libc3/sequence.h b/libc3/sequence.h
index 1adf186..a869db2 100644
--- a/libc3/sequence.h
+++ b/libc3/sequence.h
@@ -20,6 +20,7 @@
 void         sequence_clean (s_sequence *seq);
 s_sequence * sequence_init (s_sequence *sequence, f64 duration,
                             const s8 *title, f_sequence load,
-                            f_sequence render, f_sequence unload);
+                            f_sequence render, f_sequence unload,
+                            void *window);
 
 #endif /* LIBC3_SEQUENCE_H */
diff --git a/libc3/void.c b/libc3/void.c
index c5c01d1..7abd6ef 100644
--- a/libc3/void.c
+++ b/libc3/void.c
@@ -142,143 +142,86 @@ bool void_clean (const s_sym *type, void *data)
   return false;
 }
 
-bool void_init_copy (const s_sym *type, void *v, const void *src)
+void * void_init_copy (const s_sym *type, void *v, const void *src)
 {
-  if (type == sym_1("Array")) {
-    array_init_copy;
-    return true;
-  }
-  if (type == sym_1("Bool")) {
-    bool_init_copy;
-    return true;
-  }
-  if (type == sym_1("Call")) {
-    call_init_copy;
-    return true;
-  }
-  if (type == sym_1("Cfn")) {
-    cfn_init_copy;
-    return true;
-  }
-  if (type == sym_1("Character")) {
-    character_init_copy;
-    return true;
-  }
-  if (type == sym_1("F32")) {
-    f32_init_copy;
-    return true;
-  }
-  if (type == sym_1("F64")) {
-    f64_init_copy;
-    return true;
-  }
-  if (type == sym_1("Fact")) {
-    fact_init_copy;
-    return true;
-  }
-  if (type == sym_1("Fn")) {
-    fn_init_copy;
-    return true;
-  }
-  if (type == sym_1("Ident")) {
-    ident_init_copy;
-    return true;
-  }
-  if (type == sym_1("Integer")) {
-    integer_init_copy;
-    return true;
-  }
-  if (type == sym_1("List")) {
-    list_init_copy;
-    return true;
-  }
-  if (type == sym_1("Ptag")) {
-    ptag_init_copy;
-    return true;
-  }
-  if (type == sym_1("Ptr")) {
-    ptr_init_copy;
-    return true;
-  }
-  if (type == sym_1("PtrFree")) {
-    ptr_free_init_copy;
-    return true;
-  }
-  if (type == sym_1("Quote")) {
-    quote_init_copy;
-    return true;
-  }
-  if (type == sym_1("S8")) {
-    s8_init_copy;
-    return true;
-  }
-  if (type == sym_1("S16")) {
-    s16_init_copy;
-    return true;
-  }
-  if (type == sym_1("S32")) {
-    s32_init_copy;
-    return true;
-  }
-  if (type == sym_1("S64")) {
-    s64_init_copy;
-    return true;
-  }
-  if (type == sym_1("Str")) {
-    str_init_copy;
-    return true;
-  }
-  if (type == sym_1("Struct")) {
-    struct_init_copy;
-    return true;
-  }
-  if (type == sym_1("Sw")) {
-    sw_init_copy;
-    return true;
-  }
-  if (type == sym_1("Sym")) {
-    sym_init_copy;
-    return true;
-  }
-  if (type == sym_1("Tuple")) {
-    tuple_init_copy;
-    return true;
-  }
-  if (type == sym_1("U8")) {
-    u8_init_copy;
-    return true;
-  }
-  if (type == sym_1("U16")) {
-    u16_init_copy;
-    return true;
-  }
-  if (type == sym_1("U32")) {
-    u32_init_copy;
-    return true;
-  }
-  if (type == sym_1("U64")) {
-    u64_init_copy;
-    return true;
-  }
-  if (type == sym_1("Uw")) {
-    uw_init_copy;
-    return true;
-  }
-  if (type == sym_1("Var")) {
-    *dest = NULL;
-    return true;
-  }
-  if (type == sym_1("Void")) {
-    *dest = NULL;
-    return true;
-  }
+  void *r;
+  if (type == sym_1("Array"))
+    return array_init_copy(v, src);
+  if (type == sym_1("Bool"))
+    return bool_init_copy(v, src);
+  if (type == sym_1("Call"))
+    return call_init_copy(v, src);
+  if (type == sym_1("Cfn"))
+    return cfn_init_copy(v, src);
+  if (type == sym_1("Character"))
+    return character_init_copy(v, src);
+  if (type == sym_1("F32"))
+    return f32_init_copy(v, src);
+  if (type == sym_1("F64"))
+    return f64_init_copy(v, src);
+  if (type == sym_1("Fact"))
+    return fact_init_copy(v, src);
+  if (type == sym_1("Fn"))
+    return fn_init_copy(v, src);
+  if (type == sym_1("Ident"))
+    return ident_init_copy(v, src);
+  if (type == sym_1("Integer"))
+    return integer_init_copy(v, src);
+  if (type == sym_1("List"))
+    return list_init_copy(v, src);
+  if (type == sym_1("Ptag"))
+    return ptag_init_copy(v, src);
+  if (type == sym_1("Ptr"))
+    return ptr_init_copy(v, src);
+  if (type == sym_1("PtrFree"))
+    return ptr_free_init_copy(v, src);
+  if (type == sym_1("Quote"))
+    return quote_init_copy(v, src);
+  if (type == sym_1("S8"))
+    return s8_init_copy(v, src);
+  if (type == sym_1("S16"))
+    return s16_init_copy(v, src);
+  if (type == sym_1("S32"))
+    return s32_init_copy(v, src);
+  if (type == sym_1("S64"))
+    return s64_init_copy(v, src);
+  if (type == sym_1("Str"))
+    return str_init_copy(v, src);
+  if (type == sym_1("Struct"))
+    return struct_init_copy(v, src);
+  if (type == sym_1("Sw"))
+    return sw_init_copy(v, src);
+  if (type == sym_1("Sym"))
+    return sym_init_copy(v, src);
+  if (type == sym_1("Tuple"))
+    return tuple_init_copy(v, src);
+  if (type == sym_1("U8"))
+    return u8_init_copy(v, src);
+  if (type == sym_1("U16"))
+    return u16_init_copy(v, src);
+  if (type == sym_1("U32"))
+    return u32_init_copy(v, src);
+  if (type == sym_1("U64"))
+    return u64_init_copy(v, src);
+  if (type == sym_1("Uw"))
+    return uw_init_copy(v, src);
+  if (type == sym_1("Var"))
+    return v;
+  if (type == sym_1("Void"))
+    return v;
   if (struct_type_exists(type)) {
-    struct_init_copy;
-    return true;
+    s_struct s = {0};
+    s_struct t = {0};
+    struct_init_with_data(&s, type, false, v);
+    struct_init_with_data(&t, type, false, (void *) src);
+    r = struct_init_copy(&s, &t);
+    struct_type_clean(&s.type);
+    struct_type_clean(&t.type);
+    return r;
   }
   err_write_1("void_init_copy: unknown type: ");
   err_inspect_sym(&type);
   err_write_1("\n");
   assert(! "void_init_copy: unknown type");
-  return false;
+  return NULL;
 }
diff --git a/libc3/window/cairo/demo/bg_rect.c b/libc3/window/cairo/demo/bg_rect.c
index 645d4e1..2e73815 100644
--- a/libc3/window/cairo/demo/bg_rect.c
+++ b/libc3/window/cairo/demo/bg_rect.c
@@ -15,18 +15,17 @@
 #include "../types.h"
 #include "bg_rect.h"
 
-bool bg_rect_load (s_sequence *seq, s_window_cairo *window)
+#define BG_RECT_COLOR_MAX 8
+
+bool bg_rect_load (s_sequence *seq)
 {
   (void) seq;
-  (void) window;
   return true;
 }
 
-bool bg_rect_render (s_sequence *seq, s_window_cairo *window,
-                     cairo_t *cr)
+bool bg_rect_render (s_sequence *seq)
 {
-#define C3_WINDOW_CAIRO_DEMO_BG_RECT_COLOR_MAX 8
-  const s_rgb color[C3_WINDOW_CAIRO_DEMO_BG_RECT_COLOR_MAX] = {
+  const s_rgb color[BG_RECT_COLOR_MAX] = {
     {0, 0, 0},
     {1, 0, 0},
     {1, 1, 0},
@@ -38,11 +37,15 @@ bool bg_rect_render (s_sequence *seq, s_window_cairo *window,
   };
   u8 c1;
   u8 c2;
+  cairo_t *cr;
   double p;
   double q;
   s_rgb rgb;
-  c1 = (u8) trunc(seq->t) % C3_WINDOW_CAIRO_DEMO_BG_RECT_COLOR_MAX;
-  c2 = (u8) trunc(seq->t + 1.0) % C3_WINDOW_CAIRO_DEMO_BG_RECT_COLOR_MAX;
+  s_window_cairo *window;
+  window = seq->window;
+  cr = window->cr;
+  c1 = (u8) trunc(seq->t) % BG_RECT_COLOR_MAX;
+  c2 = (u8) trunc(seq->t + 1.0) % BG_RECT_COLOR_MAX;
   p = fmod(seq->t, 1.0);
   q = 1.0 - p;
   rgb.r = color[c1].r * q + color[c2].r * p;
@@ -53,3 +56,9 @@ bool bg_rect_render (s_sequence *seq, s_window_cairo *window,
   cairo_fill(cr);
   return true;
 }
+
+bool bg_rect_unload (s_sequence *seq)
+{
+  (void) seq;
+  return true;
+}
diff --git a/libc3/window/cairo/demo/bg_rect.h b/libc3/window/cairo/demo/bg_rect.h
index cd451fa..74b604b 100644
--- a/libc3/window/cairo/demo/bg_rect.h
+++ b/libc3/window/cairo/demo/bg_rect.h
@@ -15,8 +15,8 @@
 
 #include "../types.h"
 
-bool bg_rect_load (s_sequence *seq, s_window_cairo *window);
-bool bg_rect_render (s_sequence *seq, s_window_cairo *window,
-                     cairo_t *cr);
+bool bg_rect_load (s_sequence *seq);
+bool bg_rect_render (s_sequence *seq);
+bool bg_rect_unload (s_sequence *seq);
 
 #endif /* BG_RECT_H */
diff --git a/libc3/window/cairo/demo/flies.c b/libc3/window/cairo/demo/flies.c
index d1ec38b..c9a74c7 100644
--- a/libc3/window/cairo/demo/flies.c
+++ b/libc3/window/cairo/demo/flies.c
@@ -51,15 +51,13 @@ static void fly_init (s_map *map)
   (*in)++;
 }
 
-bool flies_load (s_sequence *seq,
-                 s_window_cairo *window)
+bool flies_load (s_sequence *seq)
 {
   uw address[2];
   s_array *board;
   uw i;
   uw j;
   s_map *map;
-  (void) window;
   tag_map(&seq->tag, 4);
   map = &seq->tag.data.map;
   tag_init_sym_1( map->key  + 0, "board");
@@ -128,8 +126,7 @@ bool flies_load (s_sequence *seq,
   return true;
 }
 
-bool flies_render (s_sequence *seq, s_window_cairo *window,
-                   cairo_t *cr)
+bool flies_render (s_sequence *seq)
 {
   s8 a[BOARD_SIZE];
   uw address[2];
@@ -141,6 +138,7 @@ bool flies_render (s_sequence *seq, s_window_cairo *window,
   f64 board_item_w;
   f64 board_item_h;
   s_buf buf;
+  cairo_t *cr;
   f64 dead_fly_scale;
   u8   direction;
   u8   direction_prev = 4;
@@ -159,6 +157,9 @@ bool flies_render (s_sequence *seq, s_window_cairo *window,
   cairo_text_extents_t te;
   f64 x;
   f64 y;
+  s_window_cairo *window;
+  window = seq->window;
+  cr = window->cr;
   cairo_set_source_rgb(cr, 0.5, 0.5, 0.5);
   cairo_rectangle(cr, 0, 0, window->w, window->h);
   cairo_fill(cr);
@@ -310,3 +311,9 @@ bool flies_render (s_sequence *seq, s_window_cairo *window,
   }
   return true;
 }
+
+bool flies_unload (s_sequence *seq)
+{
+  (void) seq;
+  return true;
+}
diff --git a/libc3/window/cairo/demo/flies.h b/libc3/window/cairo/demo/flies.h
index 9695712..ee04b5e 100644
--- a/libc3/window/cairo/demo/flies.h
+++ b/libc3/window/cairo/demo/flies.h
@@ -18,8 +18,8 @@
 extern s_cairo_sprite g_sprite_dead_fly;
 extern s_cairo_sprite g_sprite_fly;
 
-bool flies_load (s_sequence *seq, s_window_cairo *window);
-bool flies_render (s_sequence *seq, s_window_cairo *window,
-                      cairo_t *cr);
+bool flies_load (s_sequence *seq);
+bool flies_render (s_sequence *seq);
+bool flies_unload (s_sequence *seq);
 
 #endif /* FLIES_H */
diff --git a/libc3/window/cairo/demo/lightspeed.c b/libc3/window/cairo/demo/lightspeed.c
index 19397dc..a535d91 100644
--- a/libc3/window/cairo/demo/lightspeed.c
+++ b/libc3/window/cairo/demo/lightspeed.c
@@ -53,10 +53,9 @@ static void star_render (s_tag *star, s_window_cairo *window,
     star_init(star);
 }
 
-bool lightspeed_load (s_sequence *seq, s_window_cairo *window)
+bool lightspeed_load (s_sequence *seq)
 {
   uw i;
-  (void) window;
   tag_tuple(&seq->tag, LIGHTSPEED_STARS);
   i = 0;
   while (i < LIGHTSPEED_STARS) {
@@ -66,11 +65,14 @@ bool lightspeed_load (s_sequence *seq, s_window_cairo *window)
   return true;
 }
 
-bool lightspeed_render (s_sequence *seq, s_window_cairo *window,
-                        cairo_t *cr)
+bool lightspeed_render (s_sequence *seq)
 {
+  cairo_t *cr;
   uw i;
   cairo_matrix_t matrix;
+  s_window_cairo *window;
+  window = seq->window;
+  cr = window->cr;
   cairo_get_matrix(cr, &matrix);
   cairo_scale(cr, window->w / 2.0, window->h / 2.0);
   cairo_translate(cr, 1.0, 1.0);
@@ -85,3 +87,9 @@ bool lightspeed_render (s_sequence *seq, s_window_cairo *window,
   cairo_set_matrix(cr, &matrix);
   return true;
 }
+
+bool lightspeed_unload (s_sequence *seq)
+{
+  (void) seq;
+  return true;
+}
diff --git a/libc3/window/cairo/demo/lightspeed.h b/libc3/window/cairo/demo/lightspeed.h
index dc95059..8b89b3b 100644
--- a/libc3/window/cairo/demo/lightspeed.h
+++ b/libc3/window/cairo/demo/lightspeed.h
@@ -17,8 +17,8 @@
 
 #define LIGHTSPEED_STARS 1000
 
-bool lightspeed_load (s_sequence *seq, s_window_cairo *window);
-bool lightspeed_render (s_sequence *seq, s_window_cairo *window,
-                        cairo_t *cr);
+bool lightspeed_load (s_sequence *seq);
+bool lightspeed_render (s_sequence *seq);
+bool lightspeed_unload (s_sequence *seq);
 
 #endif /* LIGHTSPEED_H */
diff --git a/libc3/window/cairo/demo/toasters.c b/libc3/window/cairo/demo/toasters.c
index 13086e1..ea59aac 100644
--- a/libc3/window/cairo/demo/toasters.c
+++ b/libc3/window/cairo/demo/toasters.c
@@ -39,7 +39,6 @@ static s_tag * toast_init (s_tag *toast, f64 x, f64 y)
   return toast;
 }
 
-
 static void toast_render (s_tag *toast, s_window_cairo *window,
                           cairo_t *cr, s_sequence *seq)
 {
@@ -99,11 +98,9 @@ static void toaster_render (s_tag *toaster, s_window_cairo *window,
   }
 }
 
-bool toasters_load (s_sequence *seq,
-                    s_window_cairo *window)
+bool toasters_load (s_sequence *seq)
 {
   s_map *map;
-  (void) window;
   tag_map(&seq->tag, 2);
   map = &seq->tag.data.map;
   tag_init_sym_1( map->key + 0, "toasters");
@@ -113,11 +110,14 @@ bool toasters_load (s_sequence *seq,
   return true;
 }
 
-bool toasters_render (s_sequence *seq, s_window_cairo *window,
-                      cairo_t *cr)
+bool toasters_render (s_sequence *seq)
 {
+  cairo_t *cr;
   s_list **toasters;
   s_list **toasts;
+  s_window_cairo *window;
+  window = seq->window;
+  cr = window->cr;
   cairo_set_source_rgb(cr, 0.7, 0.95, 1.0);
   cairo_rectangle(cr, 0, 0, window->w, window->h);
   cairo_fill(cr);
@@ -234,3 +234,9 @@ bool toasters_render_toasters (s_list **toasters,
   }
   return true;
 }
+
+bool toasters_unload (s_sequence *seq)
+{
+  (void) seq;
+  return true;
+}
diff --git a/libc3/window/cairo/demo/toasters.h b/libc3/window/cairo/demo/toasters.h
index b97b4b9..c476e48 100644
--- a/libc3/window/cairo/demo/toasters.h
+++ b/libc3/window/cairo/demo/toasters.h
@@ -18,8 +18,8 @@
 extern s_cairo_sprite g_sprite_toast;
 extern s_cairo_sprite g_sprite_toaster;
 
-bool toasters_load (s_sequence *seq, s_window_cairo *window);
-bool toasters_render (s_sequence *seq, s_window_cairo *window,
-                      cairo_t *cr);
+bool toasters_load (s_sequence *seq);
+bool toasters_render (s_sequence *seq);
+bool toasters_unload (s_sequence *seq);
 
 #endif /* TOASTERS_H */
diff --git a/libc3/window/cairo/demo/window_cairo_demo.c b/libc3/window/cairo/demo/window_cairo_demo.c
index b8096b9..6c85ac0 100644
--- a/libc3/window/cairo/demo/window_cairo_demo.c
+++ b/libc3/window/cairo/demo/window_cairo_demo.c
@@ -88,30 +88,28 @@ bool window_cairo_demo_load (s_window_cairo *window)
   if (! cairo_font_init(&g_font_courier_new,
                         "fonts/Courier New/Courier New.ttf"))
     return false;
-  window_cairo_sequence_init(window->sequence, 8.0,
-                             "01. Background rectangles",
-                             bg_rect_load, bg_rect_render);
-  window_cairo_sequence_init(window->sequence + 1, 20.0,
-                             "02. Lightspeed",
-                             lightspeed_load, lightspeed_render);
+  sequence_init(window->sequence, 8.0, "01. Background rectangles",
+                bg_rect_load, bg_rect_render, bg_rect_unload, window);
+  sequence_init(window->sequence + 1, 20.0, "02. Lightspeed",
+                lightspeed_load, lightspeed_render, lightspeed_unload,
+                window);
   if (! cairo_sprite_init(&g_sprite_toaster, "img/flaps.png",
                           4, 1, 4))
     return false;
   if (! cairo_sprite_init(&g_sprite_toast, "img/toast.png",
                           1, 1, 1))
     return false;
-  window_cairo_sequence_init(window->sequence + 2, 60.0,
-                             "03. Toasters",
-                             toasters_load, toasters_render);
+  sequence_init(window->sequence + 2, 60.0, "03. Toasters",
+                toasters_load, toasters_render, toasters_unload,
+                window);
   if (! cairo_sprite_init(&g_sprite_fly, "img/fly-noto.png",
                           1, 1, 1))
     return false;
   if (! cairo_sprite_init(&g_sprite_dead_fly, "img/fly-dead.png",
                           1, 1, 1))
     return false;
-  window_cairo_sequence_init(window->sequence + 3, 60.0,
-                             "04. Flies",
-                             flies_load, flies_render);
+  sequence_init(window->sequence + 3, 60.0, "04. Flies",
+                flies_load, flies_render, flies_unload, window);
   window_set_sequence_pos((s_window *) window, 0);
   return true;
 }
@@ -142,17 +140,18 @@ static void render_text (cairo_t *cr, double x, double y,
   cairo_show_text(cr, p);
 }
 
-bool window_cairo_demo_render (s_window_cairo *window,
-                               cairo_t *cr)
+bool window_cairo_demo_render (s_window_cairo *window)
 {
+  cairo_t *cr;
   s_sequence *seq;
   cairo_text_extents_t te;
   assert(window);
+  cr = window->cr;
   assert(cr);
   if (! window_animate((s_window *) window))
     return false;
   seq = window->sequence + window->sequence_pos;
-  if (! seq->render(seq, window, cr))
+  if (! seq->render(seq))
     return false;
   /* text */
   cairo_set_font_size(cr, 20);
diff --git a/libc3/window/cairo/demo/window_cairo_demo.h b/libc3/window/cairo/demo/window_cairo_demo.h
index ab2b69a..32703a6 100644
--- a/libc3/window/cairo/demo/window_cairo_demo.h
+++ b/libc3/window/cairo/demo/window_cairo_demo.h
@@ -24,7 +24,7 @@ bool window_cairo_demo_button (s_window_cairo *window, u8 button,
                                sw x, sw y);
 bool window_cairo_demo_key (s_window_cairo *window, uw keysym);
 bool window_cairo_demo_load (s_window_cairo *window);
-bool window_cairo_demo_render (s_window_cairo *window, cairo_t *cr);
+bool window_cairo_demo_render (s_window_cairo *window);
 bool window_cairo_demo_resize (s_window_cairo *window, uw w, uw h);
 void window_cairo_demo_unload (s_window_cairo *window);
 
diff --git a/libc3/window/cairo/types.h b/libc3/window/cairo/types.h
index f7647fe..7893512 100644
--- a/libc3/window/cairo/types.h
+++ b/libc3/window/cairo/types.h
@@ -47,20 +47,12 @@ typedef bool (*f_window_cairo_motion) (s_window_cairo *window, sw x,
                                        sw y);
 
 /* return false to break event loop */
-typedef bool (*f_window_cairo_render) (s_window_cairo *window,
-                                       cairo_t *cr);
+typedef bool (*f_window_cairo_render) (s_window_cairo *window);
 
 /* return false to break event loop */
 typedef bool (*f_window_cairo_resize) (s_window_cairo *window,
                                        uw w, uw h);
 
-typedef bool (*f_window_cairo_sequence_load) (s_sequence *seq,
-                                              s_window_cairo *window);
-
-typedef bool (*f_window_cairo_sequence_render) (s_sequence *seq,
-                                                s_window_cairo *window,
-                                                cairo_t *cr);
-
 typedef void (*f_window_cairo_unload) (s_window_cairo *window);
 
 struct cairo_font {
@@ -111,6 +103,7 @@ struct window_cairo {
   f_window_cairo_render render;
   cairo_t              *cr;
   f_window_cairo_resize resize;
+  s_sequence           *seq;
   s_sequence           *sequence;
   uw                    sequence_count;
   uw                    sequence_pos;
diff --git a/libc3/window/cairo/window_cairo.c b/libc3/window/cairo/window_cairo.c
index 7d4728d..da4abbd 100644
--- a/libc3/window/cairo/window_cairo.c
+++ b/libc3/window/cairo/window_cairo.c
@@ -92,9 +92,11 @@ bool window_cairo_motion_default (s_window_cairo *window, sw x, sw y)
   return true;
 }
 
-bool window_cairo_render_default (s_window_cairo *window, cairo_t *cr)
+bool window_cairo_render_default (s_window_cairo *window)
 {
+  cairo_t *cr;
   assert(window);
+  cr = window->cr;
   assert(cr);
   cairo_set_source_rgb(cr, 1, 1, 1);
   cairo_rectangle(cr, 0, 0, window->w, window->h);
@@ -112,21 +114,3 @@ bool window_cairo_resize_default (s_window_cairo *window, uw w, uw h)
   printf("window_cairo_resize_default: %lu x %lu\n", w, h);
   return true;
 }
-
-s_sequence * window_cairo_sequence_init
-(s_sequence *seq, f64 duration, const s8 *title,
- f_window_cairo_sequence_load load,
- f_window_cairo_sequence_render render)
-{
-  s_sequence tmp = {0};
-  assert(seq);
-  tmp.dt = 0.0;
-  tmp.t = 0.0;
-  tmp.duration = duration;
-  tmp.title = title;
-  tmp.load = (f_sequence_load) load;
-  tmp.render = (f_sequence_render) render;
-  tag_init_void(&tmp.tag);
-  *seq = tmp;
-  return seq;
-}
diff --git a/libc3/window/cairo/window_cairo.h b/libc3/window/cairo/window_cairo.h
index be868c2..678b198 100644
--- a/libc3/window/cairo/window_cairo.h
+++ b/libc3/window/cairo/window_cairo.h
@@ -29,20 +29,13 @@ s_window_cairo * window_cairo_init (s_window_cairo *window,
                                     uw sequence_count);
 bool             window_cairo_run (s_window_cairo *window);
 
-/* Stack-allocation compatible functions, call sequence_clean
-   after use. */
-s_sequence *     window_cairo_sequence_init
-(s_sequence *sequence, f64 duration, const s8 *title,
- f_window_cairo_sequence_load load,
- f_window_cairo_sequence_render render);
-
 /* Callbacks. */
 bool window_cairo_button_default (s_window_cairo *window, u8 button,
                                   sw x, sw y);
 bool window_cairo_key_default (s_window_cairo *window, uw keysym);
 bool window_cairo_load_default (s_window_cairo *window);
 bool window_cairo_motion_default (s_window_cairo *window, sw x, sw y);
-bool window_cairo_render_default (s_window_cairo *window, cairo_t *cr);
+bool window_cairo_render_default (s_window_cairo *window);
 bool window_cairo_resize_default (s_window_cairo *window, uw w, uw h);
 
 #endif /* LIBC3_WINDOW_CAIRO_H */
diff --git a/libc3/window/cairo/xcb/window_cairo_xcb.c b/libc3/window/cairo/xcb/window_cairo_xcb.c
index 111b940..7867305 100644
--- a/libc3/window/cairo/xcb/window_cairo_xcb.c
+++ b/libc3/window/cairo/xcb/window_cairo_xcb.c
@@ -47,7 +47,7 @@ bool window_cairo_xcb_event (s_window_cairo *window,
       goto ko;
     break;
   case XCB_EXPOSE:
-    if (! window->render(window, window->cr))
+    if (! window->render(window))
       goto ko;
     xcb_gcontext_t gc = xcb_generate_id(conn);
     u32 gc_mask = XCB_GC_GRAPHICS_EXPOSURES;
diff --git a/libc3/window/sdl2/demo/bg_rect.c b/libc3/window/sdl2/demo/bg_rect.c
index dacfce0..a48df2f 100644
--- a/libc3/window/sdl2/demo/bg_rect.c
+++ b/libc3/window/sdl2/demo/bg_rect.c
@@ -15,18 +15,14 @@
 #include "../types.h"
 #include "bg_rect.h"
 
-bool bg_rect_load (s_sequence *seq, s_window_sdl2 *window)
+bool bg_rect_load (s_sequence *seq)
 {
   (void) seq;
-  (void) window;
   return true;
 }
 
-bool bg_rect_render (s_sequence *seq, s_window_sdl2 *window,
-                     SDL_GLContext context)
+bool bg_rect_render (s_sequence *seq)
 {
-  (void) context;
-  (void) window;
 #define BG_RECT_COLOR_MAX 8
   const s_rgb color[BG_RECT_COLOR_MAX] = {
     {0, 0, 0},
@@ -57,3 +53,9 @@ bool bg_rect_render (s_sequence *seq, s_window_sdl2 *window,
   assert(glGetError() == GL_NO_ERROR);
   return true;
 }
+
+bool bg_rect_unload (s_sequence *seq)
+{
+  (void) seq;
+  return true;
+}
diff --git a/libc3/window/sdl2/demo/bg_rect.h b/libc3/window/sdl2/demo/bg_rect.h
index 6bc4a8b..74b604b 100644
--- a/libc3/window/sdl2/demo/bg_rect.h
+++ b/libc3/window/sdl2/demo/bg_rect.h
@@ -15,8 +15,8 @@
 
 #include "../types.h"
 
-bool bg_rect_load (s_sequence *seq, s_window_sdl2 *window);
-bool bg_rect_render (s_sequence *seq, s_window_sdl2 *window,
-                     SDL_GLContext context);
+bool bg_rect_load (s_sequence *seq);
+bool bg_rect_render (s_sequence *seq);
+bool bg_rect_unload (s_sequence *seq);
 
 #endif /* BG_RECT_H */
diff --git a/libc3/window/sdl2/demo/earth.c b/libc3/window/sdl2/demo/earth.c
index 79171b4..891e4d4 100644
--- a/libc3/window/sdl2/demo/earth.c
+++ b/libc3/window/sdl2/demo/earth.c
@@ -24,13 +24,15 @@
 
 s_gl_sprite g_sprite_earth = {0};
 
-bool earth_load (s_sequence *seq,
-                 s_window_sdl2 *window)
+bool earth_load (s_sequence *seq)
 {
   s_map *map;
   s_gl_camera *camera;
   s_gl_sphere *sphere;
-  (void) window;
+  s_window_sdl2 *window;
+  assert(seq);
+  window = seq->window;
+  assert(window);
   camera = gl_camera_new(window->w, window->h);
   if (! camera)
     return false;
@@ -50,17 +52,17 @@ bool earth_load (s_sequence *seq,
   return true;
 }
 
-bool earth_render (s_sequence *seq, s_window_sdl2 *window,
-                   void *context)
+bool earth_render (s_sequence *seq)
 {
   s_gl_camera *camera;
   f64         *camera_rot_x_speed;
   s_map *map;
   s_gl_sphere *sphere;
   f64 sphere_radius;
+  s_window_sdl2 *window;
   assert(seq);
+  window = seq->window;
   assert(window);
-  (void) context;
   if (! seq || seq->tag.type != TAG_MAP ||
       seq->tag.data.map.count != 3) {
     err_puts("earth_render: invalid seq->tag");
@@ -132,3 +134,9 @@ bool earth_render (s_sequence *seq, s_window_sdl2 *window,
   glDisable(GL_LIGHTING);
   return true;
 }
+
+bool earth_unload (s_sequence *seq)
+{
+  (void) seq;
+  return true;
+}
diff --git a/libc3/window/sdl2/demo/earth.h b/libc3/window/sdl2/demo/earth.h
index 0bf6ac4..5f972e3 100644
--- a/libc3/window/sdl2/demo/earth.h
+++ b/libc3/window/sdl2/demo/earth.h
@@ -19,8 +19,8 @@
 extern s_gl_sprite g_sprite_earth;
 extern s_gl_sprite g_sprite_earth_night;
 
-bool earth_load (s_sequence *seq, s_window_sdl2 *window);
-bool earth_render (s_sequence *seq, s_window_sdl2 *window,
-                   void *context);
+bool earth_load (s_sequence *seq);
+bool earth_render (s_sequence *seq);
+bool earth_unload (s_sequence *seq);
 
 #endif /* EARTH_H */
diff --git a/libc3/window/sdl2/demo/flies.c b/libc3/window/sdl2/demo/flies.c
index 8c1db4d..3176666 100644
--- a/libc3/window/sdl2/demo/flies.c
+++ b/libc3/window/sdl2/demo/flies.c
@@ -54,15 +54,13 @@ static void fly_init (s_map *map)
   (*in)++;
 }
 
-bool flies_load (s_sequence *seq,
-                 s_window_sdl2 *window)
+bool flies_load (s_sequence *seq)
 {
   uw address[2];
   s_array *board;
   uw i;
   uw j;
   s_map *map;
-  (void) window;
   tag_map(&seq->tag, 4);
   map = &seq->tag.data.map;
   tag_init_sym_1( map->key  + 0, "board");
@@ -131,8 +129,7 @@ bool flies_load (s_sequence *seq,
   return true;
 }
 
-bool flies_render (s_sequence *seq, s_window_sdl2 *window,
-                   void *context)
+bool flies_render (s_sequence *seq)
 {
   s8 a[BOARD_SIZE];
   uw address[2];
@@ -161,12 +158,10 @@ bool flies_render (s_sequence *seq, s_window_sdl2 *window,
   uw random_bits = 0;
   f64 x;
   f64 y;
-  (void) context;
-  glMatrixMode(GL_PROJECTION);
-  glLoadIdentity();
-  glOrtho(0, window->w, 0, window->h, -1, 1);
-  glMatrixMode(GL_MODELVIEW);
-  glLoadIdentity();
+  s_window_sdl2 *window;
+  assert(seq);
+  window = seq->window;
+  assert(window);
   glClearColor(0.5f, 0.5f, 0.5f, 1.0f);
   glClear(GL_COLOR_BUFFER_BIT);
   /* io_inspect(&seq->tag); */
@@ -323,3 +318,9 @@ bool flies_render (s_sequence *seq, s_window_sdl2 *window,
   } glPopMatrix();
   return true;
 }
+
+bool flies_unload (s_sequence *seq)
+{
+  (void) seq;
+  return true;
+}
diff --git a/libc3/window/sdl2/demo/flies.h b/libc3/window/sdl2/demo/flies.h
index 1de8081..d365b14 100644
--- a/libc3/window/sdl2/demo/flies.h
+++ b/libc3/window/sdl2/demo/flies.h
@@ -20,8 +20,8 @@ extern s_gl_font   g_font_flies;
 extern s_gl_sprite g_sprite_dead_fly;
 extern s_gl_sprite g_sprite_fly;
 
-bool flies_load (s_sequence *seq, s_window_sdl2 *window);
-bool flies_render (s_sequence *seq, s_window_sdl2 *window,
-                   void *context);
+bool flies_load (s_sequence *seq);
+bool flies_render (s_sequence *seq);
+bool flies_unload (s_sequence *seq);
 
 #endif /* FLIES_H */
diff --git a/libc3/window/sdl2/demo/lightspeed.c b/libc3/window/sdl2/demo/lightspeed.c
index 1e9cffc..e9ad16e 100644
--- a/libc3/window/sdl2/demo/lightspeed.c
+++ b/libc3/window/sdl2/demo/lightspeed.c
@@ -61,11 +61,14 @@ static void star_render (s_tag *star, s_sequence *seq, s_gl_vertex *v)
     star_init(star);
 }
 
-bool lightspeed_load (s_sequence *seq, s_window_sdl2 *window)
+bool lightspeed_load (s_sequence *seq)
 {
   uw i;
   uw star_count;
-  (void) window;
+  s_window_sdl2 *window;
+  assert(seq);
+  window = seq->window;
+  assert(window);
   tag_tuple(&seq->tag, LIGHTSPEED_STAR_MAX);
   star_count = window->w * window->h * LIGHTSPEED_STAR_PROBABILITY;
   if (star_count > LIGHTSPEED_STAR_MAX)
@@ -78,14 +81,15 @@ bool lightspeed_load (s_sequence *seq, s_window_sdl2 *window)
   return true;
 }
 
-bool lightspeed_render (s_sequence *seq, s_window_sdl2 *window,
-                        void *context)
+bool lightspeed_render (s_sequence *seq)
 {
   uw i;
   uw star_count;
   s_gl_vertex *v;
-  (void) window;
-  (void) context;
+  s_window_sdl2 *window;
+  assert(seq);
+  window = seq->window;
+  assert(window);
   gl_matrix_4d_init_identity(&g_ortho.model_matrix);
   /*
   gl_matrix_4d_scale(&g_ortho.model_matrix, window->w / 2.0,
@@ -126,3 +130,9 @@ bool lightspeed_render (s_sequence *seq, s_window_sdl2 *window,
   assert(glGetError() == GL_NO_ERROR);
   return true;
 }
+
+bool lightspeed_unload (s_sequence *seq)
+{
+  (void) seq;
+  return true;
+}
diff --git a/libc3/window/sdl2/demo/lightspeed.h b/libc3/window/sdl2/demo/lightspeed.h
index 6a889ad..c099ed2 100644
--- a/libc3/window/sdl2/demo/lightspeed.h
+++ b/libc3/window/sdl2/demo/lightspeed.h
@@ -20,8 +20,8 @@
 
 extern s_gl_lines g_lines_stars;
 
-bool lightspeed_load (s_sequence *seq, s_window_sdl2 *window);
-bool lightspeed_render (s_sequence *seq, s_window_sdl2 *window,
-                        void *context);
+bool lightspeed_load (s_sequence *seq);
+bool lightspeed_render (s_sequence *seq);
+bool lightspeed_unload (s_sequence *seq);
 
 #endif /* LIGHTSPEED_H */
diff --git a/libc3/window/sdl2/demo/toasters.c b/libc3/window/sdl2/demo/toasters.c
index 0491655..21057d2 100644
--- a/libc3/window/sdl2/demo/toasters.c
+++ b/libc3/window/sdl2/demo/toasters.c
@@ -101,11 +101,9 @@ static void toaster_render (s_tag *toaster, s_window_sdl2 *window,
   }
 }
 
-bool toasters_load (s_sequence *seq,
-                    s_window_sdl2 *window)
+bool toasters_load (s_sequence *seq)
 {
   s_map *map;
-  (void) window;
   tag_map(&seq->tag, 2);
   map = &seq->tag.data.map;
   tag_init_sym_1( map->key + 0, "toasters");
@@ -115,12 +113,14 @@ bool toasters_load (s_sequence *seq,
   return true;
 }
 
-bool toasters_render (s_sequence *seq, s_window_sdl2 *window,
-                      void *context)
+bool toasters_render (s_sequence *seq)
 {
   s_list **toasters;
   s_list **toasts;
-  (void) context;
+  s_window_sdl2 *window;
+  assert(seq);
+  window = seq->window;
+  assert(window);
   glClearColor(0.7f, 0.95f, 1.0f, 1.0f);
   glClear(GL_COLOR_BUFFER_BIT);
   glPushMatrix();
@@ -242,3 +242,9 @@ bool toasters_render_toasters (s_list **toasters, s_window_sdl2 *window,
   }
   return true;
 }
+
+bool toasters_unload (s_sequence *seq)
+{
+  (void) seq;
+  return true;
+}
diff --git a/libc3/window/sdl2/demo/toasters.h b/libc3/window/sdl2/demo/toasters.h
index e6c9c15..ea4e3a3 100644
--- a/libc3/window/sdl2/demo/toasters.h
+++ b/libc3/window/sdl2/demo/toasters.h
@@ -18,8 +18,8 @@
 extern s_gl_sprite g_sprite_toast;
 extern s_gl_sprite g_sprite_toaster;
 
-bool toasters_load (s_sequence *seq, s_window_sdl2 *window);
-bool toasters_render (s_sequence *seq, s_window_sdl2 *window,
-                      void *context);
+bool toasters_load (s_sequence *seq);
+bool toasters_render (s_sequence *seq);
+bool toasters_unload (s_sequence *seq);
 
 #endif /* TOASTERS_H */
diff --git a/libc3/window/sdl2/demo/window_sdl2_demo.c b/libc3/window/sdl2/demo/window_sdl2_demo.c
index cd75c40..07814eb 100644
--- a/libc3/window/sdl2/demo/window_sdl2_demo.c
+++ b/libc3/window/sdl2/demo/window_sdl2_demo.c
@@ -42,8 +42,7 @@ static bool window_sdl2_demo_button (s_window_sdl2 *window, u8 button,
 static bool window_sdl2_demo_key (s_window_sdl2 *window,
                                   SDL_Keysym *keysym);
 static bool window_sdl2_demo_load (s_window_sdl2 *window);
-static bool window_sdl2_demo_render (s_window_sdl2 *window,
-                                     void *context);
+static bool window_sdl2_demo_render (s_window_sdl2 *window);
 static bool window_sdl2_demo_resize (s_window_sdl2 *window,
                                      uw w, uw h);
 static void window_sdl2_demo_unload (s_window_sdl2 *window);
@@ -160,24 +159,23 @@ bool window_sdl2_demo_load (s_window_sdl2 *window)
     return false;
   if (! gl_text_init_1(&g_text_fps, &g_font_courier_new, "0.00"))
     return false;
-  window_sdl2_sequence_init(window->sequence, 8.0,
-                            "01. Background rectangles",
-                            bg_rect_load, bg_rect_render);
+  sequence_init(window->sequence, 8.0, "01. Background rectangles",
+                bg_rect_load, bg_rect_render, bg_rect_unload, window);
   if (! gl_lines_init(&g_lines_stars) ||
       ! gl_lines_allocate(&g_lines_stars, LIGHTSPEED_STAR_MAX))
     return false;
-  window_sdl2_sequence_init(window->sequence + 1, 20.0,
-                            "02. Lightspeed",
-                            lightspeed_load, lightspeed_render);
+  sequence_init(window->sequence + 1, 20.0, "02. Lightspeed",
+                lightspeed_load, lightspeed_render, lightspeed_unload,
+                window);
   if (! gl_sprite_init(&g_sprite_toaster, "img/flaps.256.png",
                        4, 1, 4))
     return false;
   if (! gl_sprite_init(&g_sprite_toast, "img/toast.128.png",
                        1, 1, 1))
     return false;
-  window_sdl2_sequence_init(window->sequence + 2, 60.0,
-                            "03. Toasters",
-                            toasters_load, toasters_render);
+  sequence_init(window->sequence + 2, 60.0, "03. Toasters",
+                toasters_load, toasters_render, toasters_unload,
+                window);
   if (! gl_font_init(&g_font_flies,
                      "fonts/Courier New/Courier New.ttf"))
     return false;
@@ -187,9 +185,8 @@ bool window_sdl2_demo_load (s_window_sdl2 *window)
   if (! gl_sprite_init(&g_sprite_dead_fly, "img/fly-dead.png",
                        1, 1, 1))
     return false;
-  window_sdl2_sequence_init(window->sequence + 3, 60.0,
-                            "04. Flies",
-                            flies_load, flies_render);
+  sequence_init(window->sequence + 3, 60.0, "04. Flies",
+                flies_load, flies_render, flies_unload, window);
   if (! gl_sprite_init(&g_sprite_earth, "img/earth.png",
                        1, 1, 1))
     return false;
@@ -197,9 +194,8 @@ bool window_sdl2_demo_load (s_window_sdl2 *window)
   assert(glGetError() == GL_NO_ERROR);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
   assert(glGetError() == GL_NO_ERROR);
-  window_sdl2_sequence_init(window->sequence + 4, 120.0,
-                            "05. Earth",
-                            earth_load, earth_render);
+  sequence_init(window->sequence + 4, 120.0, "05. Earth",
+                earth_load, earth_render, earth_unload, window);
   assert(glGetError() == GL_NO_ERROR);
   window_set_sequence_pos((s_window *) window, 0);
   assert(glGetError() == GL_NO_ERROR);
@@ -253,21 +249,21 @@ static void render_text (s_gl_text *text, f64 x, f64 y)
   assert(glGetError() == GL_NO_ERROR);
 }
 
-bool window_sdl2_demo_render (s_window_sdl2 *window, void *context)
+bool window_sdl2_demo_render (s_window_sdl2 *window)
 {
   s_sequence *seq;
   assert(window);
   assert(glGetError() == GL_NO_ERROR);
   if (! window_animate((s_window *) window))
     return false;
-  seq = window->sequence + window->sequence_pos;
+  seq = window->seq;
   gl_matrix_4d_init_identity(&g_ortho.model_matrix);
   gl_ortho_render(&g_ortho);
   glEnable(GL_BLEND);
   glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA,
                       GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
   assert(glGetError() == GL_NO_ERROR);
-  if (! seq->render(seq, window, context))
+  if (! seq->render(seq))
     return false;
   assert(glGetError() == GL_NO_ERROR);
   /* 2D */
diff --git a/libc3/window/sdl2/types.h b/libc3/window/sdl2/types.h
index a4e3630..0f8e9de 100644
--- a/libc3/window/sdl2/types.h
+++ b/libc3/window/sdl2/types.h
@@ -63,8 +63,7 @@ typedef bool (*f_window_sdl2_motion) (s_window_sdl2 *window, sw x,
                                       sw y);
 
 /* return false to break event loop */
-typedef bool (*f_window_sdl2_render) (s_window_sdl2 *window,
-                                      void *context);
+typedef bool (*f_window_sdl2_render) (s_window_sdl2 *window);
 
 /* return false to break event loop */
 typedef bool (*f_window_sdl2_resize) (s_window_sdl2 *window,
@@ -187,6 +186,7 @@ struct window_sdl2 {
   f_window_sdl2_render render;
   SDL_Window          *sdl_window;
   f_window_sdl2_resize resize;
+  s_sequence          *seq;
   s_sequence          *sequence;
   uw                   sequence_count;
   uw                   sequence_pos;
diff --git a/libc3/window/sdl2/window_sdl2.c b/libc3/window/sdl2/window_sdl2.c
index f07c390..48fa5db 100644
--- a/libc3/window/sdl2/window_sdl2.c
+++ b/libc3/window/sdl2/window_sdl2.c
@@ -68,12 +68,10 @@ bool window_sdl2_default_motion_cb (s_window_sdl2 *window, sw x, sw y)
   return true;
 }
 
-bool window_sdl2_default_render_cb (s_window_sdl2 *window,
-                                    void *sdl_window)
+bool window_sdl2_default_render_cb (s_window_sdl2 *window)
 {
-  (void) window;
-  (void) sdl_window;
   assert(window);
+  (void) window;
   printf("window_sdl2_default_render_cb\n");
   return true;
 }
@@ -227,14 +225,14 @@ bool window_sdl2_run (s_window_sdl2 *window)
         break;
       case SDL_KEYDOWN:
         if (! window->key(window, &sdl_event.key.keysym)) {
-          err_puts("window_sdl2_run: window->key -> false");
+          err_puts("window_sdl2_run: window->key => false");
           quit = 1;
         }
         break;
       case SDL_MOUSEBUTTONDOWN:
         if (! window->button(window, sdl_event.button.button,
                              sdl_event.button.x, sdl_event.button.y)) {
-          err_puts("window_sdl2_run: window->button -> false");
+          err_puts("window_sdl2_run: window->button => false");
           quit = 1;
         }
         break;
@@ -243,7 +241,7 @@ bool window_sdl2_run (s_window_sdl2 *window)
         //int relativeY = sdl_event.motion.yrel;
         if (! window->motion(window, sdl_event.motion.x,
                              sdl_event.motion.y)) {
-          err_puts("window_sdl2_run: window->motion -> false");
+          err_puts("window_sdl2_run: window->motion => false");
           quit = 1;
         }
         break;
@@ -251,7 +249,7 @@ bool window_sdl2_run (s_window_sdl2 *window)
         if (sdl_event.window.event == SDL_WINDOWEVENT_RESIZED) {
           if (! window->resize(window, sdl_event.window.data1,
                                sdl_event.window.data2)) {
-            err_puts("window_sdl2_run: window->resize -> false");
+            err_puts("window_sdl2_run: window->resize => false");
             quit = 1;
           }
           assert(glGetError() == GL_NO_ERROR);
@@ -269,8 +267,8 @@ bool window_sdl2_run (s_window_sdl2 *window)
     }
     assert(glGetError() == GL_NO_ERROR);
     //glDrawBuffer(GL_BACK);
-    if (! window->render(window, NULL)) {
-      err_puts("window_sdl2_run: window->render -> false");
+    if (! window->render(window)) {
+      err_puts("window_sdl2_run: window->render => false");
       quit = 1;
     }
     SDL_GL_SwapWindow(sdl_window);
@@ -283,19 +281,3 @@ bool window_sdl2_run (s_window_sdl2 *window)
   SDL_DestroyWindow(sdl_window);
   return false;
 }
-
-s_sequence * window_sdl2_sequence_init
-(s_sequence *seq, f64 duration, const s8 *title,
- f_window_sdl2_sequence_load load,
- f_window_sdl2_sequence_render render)
-{
-  assert(seq);
-  seq->t = 0.0;
-  seq->duration = duration;
-  seq->frame = 0;
-  seq->title = title;
-  seq->load = (f_sequence_load) load;
-  seq->render = (f_sequence_render) render;
-  tag_init_void(&seq->tag);
-  return seq;
-}
diff --git a/libc3/window/sdl2/window_sdl2.h b/libc3/window/sdl2/window_sdl2.h
index b5f1503..e1041f3 100644
--- a/libc3/window/sdl2/window_sdl2.h
+++ b/libc3/window/sdl2/window_sdl2.h
@@ -26,12 +26,6 @@ s_window_sdl2 * window_sdl2_init (s_window_sdl2 *window,
 /* Operators. */
 bool             window_sdl2_run (s_window_sdl2 *window);
 
-/* Sequences. */
-s_sequence *     window_sdl2_sequence_init
-(s_sequence *sequence, f64 duration, const s8 *title,
- f_window_sdl2_sequence_load load,
- f_window_sdl2_sequence_render render);
-
 /* Callbacks. */
 bool window_sdl2_default_button_cb (s_window_sdl2 *window, u8 button,
                                     sw x, sw y);
@@ -39,8 +33,7 @@ bool window_sdl2_default_key_cb (s_window_sdl2 *window,
                                  SDL_Keysym *keysym);
 bool window_sdl2_default_load_cb (s_window_sdl2 *window);
 bool window_sdl2_default_motion_cb (s_window_sdl2 *window, sw x, sw y);
-bool window_sdl2_default_render_cb (s_window_sdl2 *window,
-                                 void *context);
+bool window_sdl2_default_render_cb (s_window_sdl2 *window);
 bool window_sdl2_default_resize_cb (s_window_sdl2 *window, uw w, uw h);
 void window_sdl2_default_unload_cb (s_window_sdl2 *window);
 
diff --git a/libc3/window/types.h b/libc3/window/types.h
index c14b999..91c4ab3 100644
--- a/libc3/window/types.h
+++ b/libc3/window/types.h
@@ -36,8 +36,7 @@ typedef bool (*f_window_load) (s_window *window);
 typedef bool (*f_window_motion) (s_window *window, sw x, sw y);
 
 /* return false to break event loop */
-typedef bool (*f_window_render) (s_window *window,
-                                 void *render_context);
+typedef bool (*f_window_render) (s_window *window);
 
 /* return false to break event loop */
 typedef bool (*f_window_resize) (s_window *window,
@@ -61,6 +60,7 @@ struct window {
   f_window_render render;
   void           *context;
   f_window_resize resize;
+  s_sequence     *seq;
   s_sequence     *sequence;
   uw              sequence_count;
   uw              sequence_pos;
diff --git a/libc3/window/window.c b/libc3/window/window.c
index b4550dd..95b41cc 100644
--- a/libc3/window/window.c
+++ b/libc3/window/window.c
@@ -92,8 +92,12 @@ bool window_set_sequence_pos (s_window *window, uw sequence_pos)
     return false;
   }
   window->sequence_pos = sequence_pos;
+  if (window->seq)
+    if (! window->seq->unload(window->seq))
+      return false;
+  window->seq = seq;
   io_puts(seq->title);
-  if (! seq->load(seq, window))
+  if (! seq->load(seq))
     return false;
   return true;
 }