The Moving Color glass tile is designed to dynamically change its color as the heat exposure changes. It uses special dye to achieve the color changing effect. The heat can come from warm water or radiant heat source. The Moving Color tiles can be used with any kind of water application and require common tile tools to install. When temperature is applied, color will move from black or other standard colors through the color spectrum, and then reverse to the original upon cooling. The uses of these glass tiles are limited only by your imagination. See the Moving color showcase ... The price is around $180 for 1 sq. ft of 4 x 4 Glass Tile.