These drawings relate to plane symmetry or wallpaper groups, but they differ in ways that disqualify them from the mathematical form. Like plane symmetry groups, they start with a two-dimensional pattern. There may be translations, rotations, and reflections. Beyond that, these patterns break the rules of symmetry in several ways. I generate multiple unit patterns which may be randomly selected to build the overall pattern. The patterns are isosceles trapezoids arranged radially in tracks around a center point, forming a polar grid.
