Category:Flags with rectangular symmetry

This category is intended for flags that have reflection symmetry across a horizontal axis and reflection symmetry across a vertical axis (which also entails 180° rotation symmetry because the composition of two perpendicular reflections is a 180° rotation, and the composition of two symmetries is also a symmetry). While some square flags, such as International maritime signal flags for L, N, U, and Y, have two perpendicular axes of reflection symmetry that go through the corners, those flags would not count here (if they had articles) because they do not have axes of reflection symmetry going through the midpoints of the edges like the axes of reflection symmetry of a rectangle do.