Type the correct answer in the box. Use numerals instead of words. If necessary, use / for the fraction bar. Squares ABCD and EFGH share a common center on a coordinate plane, as shown in the figure. is parallel to diagonal . Two squares with same center. The outer square is A B C D and the inner square is a diamond shaped polygon E F G H. The number of lines of reflection about which the combined figure can reflect onto itself is .