diff --git a/inc/lzy.h b/inc/lzy.h
index 1ec1fc9..463e5c4 100644
--- a/inc/lzy.h
+++ b/inc/lzy.h
@@ -47,6 +47,7 @@ enum LZY_ScanCode {
 
 /* implementation */
 #ifdef LZY_IMPLEMENTATION
+#undef LZY_IMPLEMENTATION
 #ifndef LZY_TILE_SIZE
 #define LZY_TILE_SIZE 16
 #endif