Sundials and shadow clocks were being used ... but another kind of clock! Clepsydras, or water clocks, tracked the passage of time by regulating the flow of water from one vessel to another.

Hack a Day’s very own [Jack Buffington] is throwing his hat into the ring for the Buildlounge laser cutter giveaway with his solar clock that isn’t a sundial. The theory behind [Jack]’s ...