有40个正方形,其中20个红正方形,20个黑正方形.将它们打乱排成四列,每列10个正方形(颜色不限黑、红),则各列黑正方形个数的平方和,正好等于各列红正方形个数的平方和.例如,若 There are 40 squares, of which 20 red squares and 20 black squares. Disorganize them into four columns, each with 10 squares (color is not limited to black and red), then the square sum of the number of black squares in each column, Is exactly equal to the sum of squares of the number of red squares in each column. For example, if