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如图,在正方形内画上8条线图,可以得到5个锐角三角形和3个钝角三角形。你能只画4条线或图同样能使图上出现5个锐角三角形和3个钝角三角形吗?
As shown in the figure, draw 8 lines in the square, you can get 5 sharp triangles and 3 obtuse triangles. Can you draw only 4 lines or figures in the same way that 5 sharp triangles and 3 obtuse triangles appear on the figure?