A 13-year old boy gave up his iPod for a week and used an old Sony Walkman instead. It took him 3 days to realize there was a flip side to the cassette tape. (I once owned the same Walkman model that he used.) His reactions are quite interesting and show how far we’ve come in the area of portable music. On another note, the Walkman was recently named as the top music invention in the last 50 years.