Fixed #11350

core/src/mindustry/world/blocks/logic/CanvasBlock.java

@@ -68,6 +68,8 @@ public class CanvasBlock extends Block{
         clipSize = Math.max(clipSize, size * 8 - padding);
 
         previewPixmap = new Pixmap(canvasSize, canvasSize);
+
+        if(!Mathf.isPowerOfTwo(palette.length)) throw new RuntimeException("Non power-of-two palettes for canvas blocks are not supported.");
     }
 
     @Override