Otherwise known as The Michael Larson Incident.
Inside the director’s booth, a wave of fear was slowly crashing over the producers. The broadcast pace of Press Your Luck required evenly-spaced commercial breaks, timed to coincide with a player eventually hitting a Whammy. The player would go bankrupt, the action would stop, and host Peter Tomarken could take a well-needed pause for a drink of water, a squirt of hair spray, and a dabble of make-up.
But there was something Michael Larsen hadn’t told anyone.
Back in his home state of Ohio, he didn’t have just one television, he had several. Each television was hooked up to a private networking farm of VCRs in his living room. In November of 1983, he recorded every episode of Press Your Luck over the course of several weeks. He studied these videotapes, slowed them down, and froze the images to examine randomized tile sequences frame by frame. If you haven’t already guessed, Michael Larsen discovered that the Big Board on Press Your Luck was not a randomized display, but an iterative, sequential pattern which gave itself away once you knew what to look for.
(via Schneier on Security)