9 Was 6 If. The two chairs change in colour every 4th minute. What looks like two ordinary chairs on display, is in fact two totally modified replicas holding an internal water system. This allows the chairs to change in temperature, as cold or hot water is pumped through their system. The changing temperature affects the surface of the chairs, coated with thermochrome (heat-reacting) paint. When the chair is cold, it is black, but when heated up it turns white. By Christian Andersson.