Teaching The Keystone of our Religion

I’ve been looking for ideas for how to teach about keystones during Seminary next year, and it seems I’m not the only one.  The interest stems from a quote by Joseph Smith that says: 

I told the brethren that the Book of Mormon was the most correct of any book on earth, and the keystone of our religion, and a man would get nearer to God by abiding by its precepts, than by any other book. (Joseph Smith)

This morning I spent a few minutes looking up information on keystones, and I found several ideas that are helpful.  The most surprising one for me was the idea of using an old ice cube tray to make blocks out of plaster of Paris.

Anyway, here’s a list of ideas that can help teach about the purpose of a keystone in architecture:

Please share your ideas below, too!