There is an art glass sale once a year in the spring on campus, and they start selling promptly at noon. For a few years you could hover but you couldn't pick it up. Then in later years you could pick it up but you couldn't buy it. Now it is listed at promptly at noon and the faculty and staff go over and buy the cheaper pieces early and the off-campus folks with the big bucks come in to buy at noon.

I believe this must also qualify as an explanation of relativity.

SRS