“一个蚂蚁掉入水中,从水里爬上来,每爬一步在地面上留下一个湿点。所有的湿点总的看起来象什么呢?象条细绳,象条曲线。再如,这里有一个碾子,牵一头毛驴套在碾子的木杆上,它走过的路是个圆形,它所经过的任何一点距碾的 ”An ant fell into the water, climbed up from the water, every step on the ground to leave a wet point .All wet spots in general what looks like? Like a thin rope, elephant curve. Again, Here is a roller, a donkey set a roller in the wood on the pole, it is a circular road, it passes through any point away from the grind