heat's colour by davide radaelli from italy

"Heat's colour" is a radiator which is covered with a not-toxic thermochromic paint.
Thus, once the radiator is off, cold, the paint's pigment remains neutral (white, grey, transparent), but once the radiator gets warmer and warmer the pigments change colour according to the radiator's temperature.
It's also possible to use a colored pigment so that the radiator can be coloured even when it's off.