A recent call into the local photo framer, yielded a free supply of good quality card in a variety of colors as shown below.
But now I need to put on my thinking cap as to how to use this material to good effect in my classes! Below are a few ideas and links, but please add comments about any ideas you have.
1. Years ago I recall a puzzle that simply used four square tiles. I think it was part of the UK Smile project? One arrangement of the tiles is shown. How many different arrangements are there?