Seth Goldstein is a biomedical engineer who retired in 2002 after a 31-year career at the National Institutes of Health. Since then, he’s pivoted into mechanical sculptures. Here’s an article about his latest: an exercise bike that scratches his back and delivers him cookies while he pedals.
By pedaling the stationary bike, Goldstein triggers a chain reaction that causes the machine to scratch his back, fan him, pour him a mug of water and — if he really earns it — serve him a cookie.
All told, the device features five chains, six bands and 10 timing belts transferring motion throughout the system. Each cycle finishes with the deflation of a balloon, which releases a barrier blocking the cookie. The baked good then falls onto a turntable before a conveyor belt brings it to Goldstein. As long as he keeps pedaling, the process repeats.
“One of my principles when I make things is I want to have it be a cycle, so that the thing resets itself,” Goldstein says. “I like that feature.”
Personally, my favorite Rube Goldberg machine shall always be this bit from Sesame Street.