Quadruple mathematics
I didn't send you a picture, but I'll tell you something. Start from the upper left, go straight down through the lower left point, keep going, then connect the lowest midpoint with the rightmost midpoint, don't stop on the diagonal of the horizontal line of the first line, then connect the three points in the first line to the left, and then connect them to the diagonal of the lower right when you reach the upper left point.