The Shadow Knows

I believe this is by the great cartoonist and puzzler A.W. Nugent (about whom we will be hearing more).

I like this for a few reasons.

First, as a creativity exercise it brings in new and unusual shapes and gives the students open-ended instructions in how to deal with them.

Second, it helps build intuition about geometry (particularly projective geometry).

Third, it looks like fun.

The one change I would make would be to get different shapes from the same crumpled piece of paper by moving the light source.