One, two, three, four, so on each level of the picture I'm drawing, I've seem only to be looking at each number once.
,2,3,4,可见,在我画的,这幅图的每一层上,对每个数字,都只会用到一次。
On each level in the picture, I'm touching each number once, alright.
在这幅图的每一层上,我只会移动每个数字一次。
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