This piece consists of a large glass cylinder, that is filled with water and tiny glass beads. Here, a stream of water is pumped up through a bed of sand. In fitful spurts, the water bursts from the sand in a meandering eruption that never settles in one place. Sand may seem solid enough when you walk on the beach, but sand with water flowing through it can become a heavy liquid. Natural springs that well up through sand look a lot like what you see here.