On the way home from a haircut my 11-year-old son Timothy said, "Dad, I'd like to invent something."

"What's that?"

"If somebody lost a hand, wouldn't it be cool to give them a robotic hand that attached to their nerves and worked like a regular hand?"

"Yeah, DARPA's working on that. They call it the Luke Skywalker arm."

"Cool - because of how Luke's hand was replaced at the end of Empire Strikes Back? Will it be that good?"

"I'm sure it won't look that lifelike. Not at first, but its a whole lot better than what they've got now."

"Well," Timothy said, "I'd make mine a hollow robotic hand that helped the person grow a new hand inside of it."

"Wow. Okay, now that's a good idea. So, it would be a prosthetic and a regrowth chamber?" Timothy noded. "Cool. But how would it work? How would it help somebody regrow their hand?"

"I don't know. Nanobots or stem cells or something."

That kid's been listening to FastForward Radio.