 The fountain uses 11 @,@ 000 imperial gallons ( 50 @,@ 000 L ) per hour , 97 % of which is recycled back into the system . <unk> the water to the spout took ingenuity . Although consideration was given to <unk> a LED tile , it was determined that the images would then look as though they were each missing a tooth . Instead , one tile in each tower is <unk> about 6 inches ( 150 mm ) to allow the installation of 1 inch ( 25 mm ) clear <unk> for the water nozzle . The water regularly spills over the fountain and down the sides of the towers and intermittently <unk> from the nozzle . Two essential custom fittings contribute to the artistic vision of the fountain : a custom glass block at the upper edge for guiding the water 's descent while remaining <unk> , and a plastic nozzle fitted to the stainless steel frame to control the rate of water flow and reduce liability to the city for any injuries sustained by the fountain 's interactive participants . The interactive participants are usually children playing in the stream from the water spout or under the cascade . The risk that the spouting water would knock people down made the design both a legal and a physical challenge . 
