Michael Colombo spotted a man on a New York City train wearing this tattoo. He said that it's a schematic for a guitar amplifier circuit. Colombo notes that such tattoos, no matter how they might look now, could be very useful to a post-apocalyptic society that needs to preserve knowledge. If you were to get a tattoo for this purpose, what information would you preserve?
Link
Anyone remember a sci-fi short story about a futuristic society that was trying to launch a rocket into space, but as it turns out they had risen from the ashes of a previous Earth who nuked themselves into caves for many years, and none of their knowledge of electricity was preserved. Instead, they were depending on mechanical controls only, and kept having launch failures until one guy figured out the key to electrical control.
I can't recall the title.
And of course the first thing I would want after the worlds blown to hell is a guitar amp.