论文部分内容阅读
如图,A、B、C、D 4张卡片的不同位置画有黑点。如果把这些点挖空,并且不旋转地将4张卡片重叠起来,请问有哪几个孔可以穿透?
As shown, A, B, C, D 4 cards draw black spots in different positions. If these points are hollowed out and the four cards are stacked without rotation, what holes can penetrate?