I love doing this lesson with my third graders. The generous teacher in the classroom before me left a laminated set of 30 tangrams, and so I did some research and was led to Grandfather Tang. It's a great story where the two main animal characters change into different creatures as the story progresses. As I read it out loud, the kids manipulate their tangrams to match the creature. For some of them, it's hard at first, but they get better!