In fig. X, the upper triangular half of the paper has been folded over the lower half. In fig. Y, the paper is refolded to a quarter triangle. In fig. Z, a square has been punched in the folded paper. Clearly, the square will appear ineach of the trianglular quarters of the paper. Thus, when the paper is unfolded, four squares will appear symmetrically over it and it will resemble fig. (C).