Wow, this is so cool. The tiles shown here are Moving Color glass tiles
which are designed to change color when warm water or any radiant heat source effects them. The tiles come in three ttypes, Northern Lights, shown here, which appear black at room temperature and move through the color spectrum, Watercolor which come in eight colors and shift from colored to colorless when exposed to heat and Tye Dye which mimics the look of a tie-die shirt. One square foot of tile costs $180.