First, let's make a coordinate diagram, with 3 squares on the horizontal axis and 5 squares on the vertical axis. That is to say: if there are five cards, the number of squares added up to each card is 15, and the number of squares added up to six cards is also 15, which is the key.

Then, let's list the possible situations of the rectangle and look at your coordinate map.

1* 1 2*2 3*3 (4*4 is impossible, it can't be put down, and it won't work if it's above 4, so 4 has been circled, that's all)

1*2 2*3

1*3

1*4

1*5

Then let's consider 3*3 first. When you put down 3 * 3, it has already occupied 9 squares, leaving 6 squares. That means that the remaining four rectangles are not only different, but also add up to only six squares, which is obviously impossible. Excluding 3*3

Consider 2*3, occupying 6 squares, leaving 9 squares, and the remaining 4 rectangles can't be the same, adding up to only 9 squares, that is, you should use the smallest 1 * 1 * 2, 1 * 3, 1 * 4 at least 14.

So now there are only six rectangles1*11* 21* 31* 41* 52 * 2 to combine. As a result,

1*11* 21* 31* 41* 5 happens to be 15, which is enough. It can be made into pieces of paper, which is convenient for you to organize by yourself.

find

1*11* 21* 31* 41* 52 * 2, these six pieces add up to more than 15, so six pieces won't do.