Spatial Systems Laboratory:
Spring 2001 Tee-shirt
FRONT:

The image on the front is an illustration from part of the proof of the
Baxter permutation theorem.
BACK:

The image on the back is a large hexagonal fully-packed loop-state,
colored in.
To find out what the pictures on the shirts mean, go to
http://jamespropp.org/shirt3.html.