It can't be ruled out that you are wrong. Euler once guessed that Euler of order n=4t+2 does not exist for any nonnegative integer t. When t= 1, this is a problem for 36 officers, and when t=2, n= 10, mathematicians construct Euler squares of order 10, which shows that Euler conjecture is wrong. But by 1960, mathematicians had completely solved this problem and proved the existence of Euler square of order n=4t+2(t≥2). This kind of square matrix is called orthogonal latin squares in modern combinatorial mathematics, which is widely used in industrial and agricultural production and scientific experiments. It has been proved that, besides the 2nd and 6th order, other 3rd, 4th, 5th, 7th, 8th, ... orders can be manufactured.