This was a challenge, as they had to use math language (edges, vertices, angles) so we made a diagram together to get started. Students could then either add more of their own ideas independently, or keep working with the group on ideas together.
My computer has decided to be difficult and won't let me upload the pictures I have of this activity. It turned out to be full of rich, hands-on learning. And, best of all, no injuries from the toothpicks!
Since I am unable to upload the real deal, here is a picture just to give you an idea. The prisms were made out of paper. Kids decorated them and then glued them together.
The skeleton cubes were made from toothpicks and plasticine.
What hands-on learning have you tried with Geometry? I'd love to hear about it!