During a recent trip I waited for my suitcase after a heavily loaded flight from Atlanta to Los Angeles. As the various baggage items appeared on the conveyor, I reflected on the general problem of pattern recognition. The bags came in various shapes, colors, sizes, and orientations: my eyes casually scanned them as they appeared, and I found that I could quickly dismiss those that did not match my mental image of my own bag. I immediately recognized my bag when it appeared (it does have some distinctive scars after years of service) and resumed my trip to the hotel. While I was waiting, I also found time to observe the people gathered in the baggage area to see if there was anyone I recognized. Again, I was reminded of how subtle differences in facial expression, posture, and general body style allow us to instantly recognize people we know.