if (x < w && (b & U))
draw_rect(dr, WINDOW_OFFSET + TILE_SIZE * x - TILE_SIZE/24,
WINDOW_OFFSET + TILE_SIZE * y - TILE_SIZE/24,
if (x < w && (b & U))
draw_rect(dr, WINDOW_OFFSET + TILE_SIZE * x - TILE_SIZE/24,
WINDOW_OFFSET + TILE_SIZE * y - TILE_SIZE/24,