I've written a tree-like layout to help myself remember which polygons are sub-types of others, because I always get confused. I was just wondering if this is right:
|quadrilateral |parallelogram |rectangle |square |oblong |rhomboid |kite (corrected after rschwieb's answer, a rhombus is a kite) |rhombus |square |trapezoid(AmE) / trapezium (BrE) |trapezium(AmE) / irregular quadrilateral
So a square is a rhombus and a parallelogram.
Also, I know that there are two definitions of "trapezoid." Under the inclusive definition "trapezoid" is immediately under "quadrilateral" in the tree and above parallelogram and kite. Under this definition all squares are trapezoids.
Is my tree correct, at least ignoring the difference in the trapezoid definition difference?
Edit: Thanks to rschwieb for helping me realise that a rhombus is a kite. There is also a nice Euler diagram Wikipedia