Did you see the novel water-driven pendulum clock a while back? The creator, Nigel Loller, has a new clock -- this one that is powered by a laminar jet of water that shoots over the the top of the mechanism. Very clever and very dramatic. This clock makes use of a tidy pin wheel escapement.
From the YouTube description of the clock:
Water clock, made from polished 316 stainless steel and acetal. The power for this clock comes from a laminar flow water jet which 'arrives' in collector with an overflow bypass tube and is then directed onto the right hand side of the escapement pin wheel. The foam band around the escapement wheel holds the bypass corrected weight of water (30 grams) to allow the clock to run easily, but not to supply so much power that the escapement is 'hammered'. The shape of the clock is arranged to catch any splashes, to support the lam-jet, and to fit the pump and 10Ltr of water all while having to look beautiful!
Indeed! This is a very impressive bit of engineering. The clock took three weeks to construct.
See more water-driven wonders by Nigel Loller on his YouTube channel.