children`s grinders and sluices in a paved riverbed where water can flow in gutters. seamlessly undulating terrain of paving stone

artificial bent can channel children childrens circle cobblestone concrete cube curve curves dike ditch drain floor flow fountain garden gold gray grinders groove gutter gutters japanese kids metal middle mill mining paved paving pebble pebbles play playground playing river riverbed road round rows schoolyard seamlessly sewage side sidewalk silver sluices stainless steel stone stones stream terrace terrain toboggan trough undulating water wave well wheel where zen