This GeoGebra file is designed for a computer lab setting with 1:1 or few:1 student:computer use. It can also be used as a front-of-class exploration on a SMARTBoard. The exploration starts with shapes that appear to be identical. But, behind the scenes, they have been constructed to behave differently. The invitation is to allow students to interact with the points on the shapes and see how they behave. If they understand the different types of quadrilaterals and their definitions, they should be able to test their understanding. I think this is a fun and engaging way to provide a formative assessment of students' understanding.
The link to the right under the picture will take you to the actual interactive GeoGebra file.