No, a square is a rhombus and a kite, same as a rectangle is a kite, so both should be kites. And both are also trapezoids, so they should be trapezoids too. And paralellograms. And of course all of these are quadrilaterals. A square is also a The idea of geometric objects in a hierarchy leads to either incorrectness or problems in the implementation (most of the time both ;). Just don't do that.