“South Africa’s Roundabout PlayPump is powered by a very unusual source: a merry-go-round. As kids play on the merry-go-round, the rotation pushes a reciprocating pump that pulls water from a well up into a small water tower, for storage. Villagers can then get water at their convenience from a faucet. Billboards on the water towers providing public health messages and commercial advertisements pay for the system’s maintenance and repair.”

Worldchanging. Ed. Alex Steffen. NY: Abrams, 2011. 159. Print.