Let’s say you’re riding your bike around town and suddenly you have the urge to launch tennis balls at something or someone. Thanks to this inventor, you can satisfy that urge and launch away. It’s completely eco-friendly too, built from two recycled bikes, scrap steel and wood, even a leaking water jug and a lacrosse stick.

Pretty simple but genius way to make a tennis ball launcher. As you pedal the bike, you power 2 other bike wheels that launch the balls. Perfect if you like to ride your bike to the Tennis court. Or just blast pedestrians and the like.