I attended a session about how to help students better understand geometry
and properties of shapes, as opposed to just thinking about "what they look like".
We had to make a rectangle that would stay being a rectangle no matter how the
sides or vertices are dragged. We accidentally made a square first, which struck us as
odd because squares have more restrictions/conditions than a rectangle and should
be "harder" to make (our accident was a quirk of the way the program works).