You may or may not recall the Hypercolor t-shirts that came out in the 80s that changed color when exposed to heat. Being the big doofus that I am, I had two- despite living in a country that was pretty much always brain-boilingly hot, so it was only cool when I wore it indoors and my shoulders would turn my orange t-shirt yellow or my purple t-shirt pink. I wore them during my tomboy days and so promptly abandoned them to the depths of my closet when I started to "blossom" into a young lady and didn't want my newfound, much-hated tits highlighted in a different color.
Anyway, thankfully those days are gone, but they're not forgotten as you can see with this heat sensitive paint. They also make a wall paint, which would look vile if you had kids putting their warm paw and butt prints all over the living-room. Guests would think you've got brats running rampant with paint.
And you know damn well if you had a car painted with their heat sensitive paint that some joker in the neighborhood would be sure to make a rude impression just before you leave the house for work and you'll be praying the air is warm enough to erase all evidence of the penis-shaped mark on your door. Or is that just something I would do?
Class. Pure class.