| with interactive animation illustrating a rectangle that becomes a 'crossed rectangle', making a good case for regarding a 'crossed rectangle' as a type of rectangle | |
|---|---|
| A Study of Definition", Information Age Publishing, 2008, pp | Owen Byer; Felix Lazebnik; Deirdre L |
Zalman Usiskin and Jennifer Griffin, "The Classification of Quadrilaterals.
10.
23.
17