diff --git a/game/BUILD b/game/BUILD
index c0eeff6..eda6a89 100644
--- a/game/BUILD
+++ b/game/BUILD
@@ -1,7 +1,23 @@
+load("@bazel_skylib//rules:run_binary.bzl", "run_binary")
+
 cc_library(
     name = "game",
-    srcs = glob(["*.c"]),
-    hdrs = glob(["*.h"]),
+    srcs = glob(["*.c"]) + [":art/game_demo_sprites.c"],
+    hdrs = glob(["*.h"]) + [":art/game_demo_sprites.h"],
     visibility = ["//visibility:public"],
     deps = ["//device:device", "//sys:sys"]
+)
+
+run_binary(
+    name = "game_demo_sprites",
+    args = [
+        "game_demo_sprites",
+        "256",  # n sprites
+        "0",  # key color
+        "$(location :art/game_demo_sprites.png)",
+        "$(location :art/game_demo_sprites.c)"
+    ],
+    srcs = [":art/game_demo_sprites.png"],
+    outs = [":art/game_demo_sprites.c"],
+    tool = "//pytools:spritesheet",
 )
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diff --git a/game/art/game_demo_sprites.h b/game/art/game_demo_sprites.h
new file mode 100644
index 0000000..f400544
--- /dev/null
+++ b/game/art/game_demo_sprites.h
@@ -0,0 +1,8 @@
+#ifndef CROCPARTY_GAME_DEMO_SPRITES_H
+#define CROCPARTY_GAME_DEMO_SPRITES_H
+
+#include "sys/sys.h"
+
+sys_sprite game_demo_sprites[256];
+
+#endif  // CROCPARTY_GAME_DEMO_SPRITES_H
\ No newline at end of file
diff --git a/game/art/game_demo_sprites.png b/game/art/game_demo_sprites.png
new file mode 100644
index 0000000..3a08325
Binary files /dev/null and b/game/art/game_demo_sprites.png differ
diff --git a/pytools/BUILD b/pytools/BUILD
index f30b13f..c0081b6 100644
--- a/pytools/BUILD
+++ b/pytools/BUILD
@@ -8,4 +8,14 @@ py_binary(
         requirement("Jinja2"),
     ],
     visibility = ["//visibility:public"],
+)
+
+py_binary(
+    name = "spritesheet",
+    srcs = ["spritesheet.py", "shared.py"],
+    deps = [
+        requirement("pillow"),
+        requirement("Jinja2"),
+    ],
+    visibility = ["//visibility:public"],
 )
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diff --git a/pytools/font.py b/pytools/font.py
index a186701..e14afbd 100644
--- a/pytools/font.py
+++ b/pytools/font.py
@@ -26,7 +26,6 @@ def main(font_name, n_glyphs, fname_png, fname_c):
 
 def load_glyphs(fname_png: str):
     width, height, data = shared.load_image(fname_png)
-    monochrome = [pixel_to_monochrome(p) for p in data]
 
     glyphs = []
     for gy in range(0, height, 8):
@@ -36,7 +35,7 @@ def load_glyphs(fname_png: str):
                 for px in range(0, 8):
                     x = gx + px
                     y = gy + py
-                    if monochrome[y * width + x]:
+                    if pixel_to_monochrome(data[y * width + x]):
                         glyph |= 1 << (py * 8 + px)
             glyphs.append(glyph)
 
diff --git a/pytools/spritesheet.py b/pytools/spritesheet.py
new file mode 100644
index 0000000..344284b
--- /dev/null
+++ b/pytools/spritesheet.py
@@ -0,0 +1,95 @@
+from typing import Tuple
+from PIL import Image
+import sys
+import shared
+
+TEMPLATE = """
+// generated code! be nice!
+#include "sys/sys.h"
+sys_sprite {{spritesheet_name}}[{{n_sprites}}] = {
+    {% for sprite in sprites -%}
+    { .pixels={ 
+        {% for row in sprite -%}
+        { {{ row|join(",") }} }{% if not loop.last %},{% endif %}
+        {% endfor %}
+    } }{% if not loop.last %},{% endif %}
+    {%- endfor %}
+};
+""".lstrip()
+
+
+def main(spritesheet_name, n_sprites, key_color, fname_png, fname_c):
+    sprites = load_sprites(fname_png, key_color)
+    assert(len(sprites) == n_sprites), f"must be exactly {n_sprites} sprites"
+
+    with open(fname_c, "wt") as output:
+        output.write(
+            shared.templates.from_string(TEMPLATE).render(
+                spritesheet_name=spritesheet_name,
+                n_sprites=n_sprites,
+                sprites=sprites,
+            )
+        )
+
+
+def load_sprites(fname_png: str, key_color: int):
+    width, height, data = shared.load_image(fname_png)
+
+    sprites = []
+    for gy in range(0, height, 8):
+        for gx in range(0, width, 8):
+            pixels = []
+            for py in range(0, 8):
+                row = []
+                for px in range(0, 8):
+                    x = gx + px
+                    y = gy + py
+                    pal = pixel_to_palette(data[y * width + x], key_color, x, y)
+                    row.append(pal)
+                pixels.append(row)
+            sprites.append(pixels)
+
+    return sprites
+
+
+palette_colors = {
+    (0, 0, 0): 0,
+    (29, 43, 83): 1,
+    (126, 37, 83): 2,
+    (0, 135, 81): 3,
+    (171, 82, 54): 4,
+    (95, 87, 79): 5,
+    (194, 195, 199): 6,
+    (255, 241, 232): 7,
+    (255, 0, 77): 8,
+    (255, 163, 0): 9,
+    (255, 236, 39): 10,
+    (0, 228, 54): 11,
+    (41, 173, 255): 12,
+    (131, 118, 156): 13,
+    (255, 119, 168): 14,
+    (255, 204, 170): 15,
+}
+
+
+def pixel_to_palette(rgba, key_color, x, y):
+    (r, g, b, a) = rgba
+
+    if a < 128: 
+        return 255
+
+    rgb = (r, g, b)
+    ix = palette_colors.get(rgb)
+    if ix is None:
+        raise ValueError(f"unrecognized color at ({x}, {y}): {rgb}")
+
+    if ix == key_color:
+        return 255
+
+    return ix
+
+
+if __name__ == "__main__":
+    assert len(sys.argv) == 6, \
+        "there must be five args (spritesheet name, n sprites, key color, src png, out c)"
+    main(sys.argv[1], int(sys.argv[2]), int(sys.argv[3]), sys.argv[4], sys.argv[5])
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