anchor.diff:    // init other variables here
     blocksPerWidth = (width / 10).floor();
     blocksPerHeight = (height / 10).floor();
  -  data = List.generate(
  -      blocksPerHeight, (e) => List.generate(blocksPerWidth, (e) => 0));
  +  data = List.filled(blocksPerHeight, List.filled(blocksPerWidth, 0));
   
     resetGame();
   }
  
positive.code:             }
              break;
            case VK_DOWN:
              if (direction.y != -1) {
                direction.x = 0;
                direction.y = 1;
  
negative.code:       } else if (direction.y == 1) {
          // down
          snakePoints[i].y += 1;
          if (snakePoints[i].y >= (bitmapHeight / 10).floor()) {
            snakePoints[i].y = 0;
          }
        } else if (direction.y == -1) {
  