Remember Hypercolour? You know, those T-shirts that signalled to observers whenever you were sweating? Well, now you can get it as a paint. Materials specialist, Alsa Corp, has developed a new multi-coat paint that goes from black to white or from blue to white when exposed to heat. Furthermore, by painting over it with a special, transparent topcoat called a "candy", you can create heat-induced colour changes from black or blue to virtually any hue that takes your fancy! Even if you don't want to paint your walls with the stuff, it could be fun to put on your car, so others know when you're going really fast.