diff --git a/assets/def.go b/assets/def.go
index 4524c96..8c6691a 100644
--- a/assets/def.go
+++ b/assets/def.go
@@ -9,6 +9,8 @@ import (
 //go:embed sprites.png
 var Sprite []byte
 
+const BLOCK_TILE_SIZE = 16
+
 var Font = font.TileFont{
 	Charmap: map[rune]byte{
 		'a': 0x20,