There's a beep that's been on every Mac for 35 years, and its name secretly means "so sue me." It was aimed at the Beatles, and it only got past Apple's lawyers because the engineer who made it told them it was a Japanese word. That beep is one of the 21 Apple sounds A.G. Cook stitched into the song that opened Apple's MacBook Pro event five years ago today. You can watch him mic up an old iMac G3 in a garage, record the startup chime into Logic Pro, and then pile on the iPod click wheel, the…