In the '70s, it was mood rings. In the '80s, clothing. Want to get your hands on a timeless therm-chronic product? Try our Hypercolour Thinking Putty! This groovy putty changes colour with just the heat of your hands. The awesome effect makes it perfect for twists, duo-toned sculptures, 5-minute breaks, and other timeouts. Put it in the fridge then against a warm coffee mug to experience an even more intense colour change.