The Kemeny/Haldeman project page notes that the patterns in the building’s decorative brick display a Fibonacci sequence (0, 1, 1, 2, 3, 5, 8, etc.). The pattern comprises a field of soldier-course bricks from which certain bricks protrude.
The Math Department’s previous headquarters, Bradley Hall (connected to Gerry Hall as the “Shower Towers”), was known to display some pattern in the arrangement of its blue, green, and white tiles, although what it represented did not seem to be commonly known.
[Update 12.31.2006: information on pattern added.]