The twist is that the zigs and zags change in size and spacing as they go from the outskirts toward the middle of the island: each zigzag is half the width of the previous one.

• 关键是由岛屿外围往中心前进时，这些矩形锯齿的宽度与间隔会慢慢变化：每个锯齿的宽度都是前一个的一半。