Squaring the square 21 steap

21steap is smallest of squaring the square

Warning

don't look at the image below if you want to do it yourself

TIPS: the shell is too biger of it because I use PETG to pinter that ,if you guys can find suitable size, uploading

If you use 0.4nozzle you can't see the I don't use 0.2 nozzle to make that, because I don't have if you can use 0.2 nozzle please uploading

Mathematicians once spent so much effort without any results that in 1930 the famous Soviet mathematician Lukin conjectured that it was impossible to divide a square into a finite number of squares of different sizes. Mollen challenged this conjecture and offered a solution: if there are two different square divisions of the same rectangle, and each square in one of the divisions is different from each square in the other division, then adding two squares to the two divisions (which are different from either of the two divisions) creates a perfect square. Before this, the perfect rectangle has had relatively rich results. In 1939, Sprague succeeded in constructing a perfect square of order 55 according to Mollen's idea, with a side length of 4205. A few months later, the perfect square with a smaller order (28 orders) and shorter sides (1015) was constructed by four undergraduates at Trinity College, Cambridge. In 1948, Wilcox constructed a 24-order perfect square, but it contained a perfect rectangle (such squares are called mixed perfect squares). A square constructed entirely of squares is called a pure perfect square. This record was not broken until 1978. In 1967, Wilson constructed the perfect square of order 25 and 26. In 1962, Duivestine of the Technical University of Twente in the Netherlands proved that there is no perfect square below the 20th order. In 1978, with the help of computer technology, Duivistin successfully constructed a perfect square of order 21, which is unique, and it is not only the lowest order, but also the number is simpler, in addition to the structure it also has many beautiful features, such as some powers of 2 just located on a diagonal, and so on. Duivestine also proved that a perfect square below the 21st order does not exist. In 1982, With the help of computer technology, Duistin successfully constructed a perfect square of order 21, which is unique, and it is not only the lowest order, but also the number is simpler, in addition to the construction of it has many beautiful features, such as some powers of 2 just on a diagonal, and so on. Duivestine also proved that a perfect square below the 21st order does not exist. In 1982, Duivestine proved that there are no mixed perfect squares below the 24th order. In 1992, Bukam and Duivistin gave 207 pure perfect squares of order 21 to 25: order 21, 22, 23, 24, 25 numbers 1, 8, 12, 26, 160, putting a temporary end to the discussion of perfect squares. But mathematicians did not stop their research, and they studied whether squares of different sizes could fill the whole plane, and they also extended the problem of perfect partition to Mobius strips, cylinders, torus, and Klein bottles, and achieved many interesting results. But cube filling turned out to be absent