Jonah turned off his electronic timer and resumed his phone conversation. "That timer's a lifesaver. I'd already forgotten I was boiling water for coffee. Without my timer, the water might've boiled completely out of the pot. My memory's like yours. I don't know how many times I've gone out and then wondered, Did I turn off the gas?" His mom said, "I have such a simple solution for you. Just grab a yellow Post-it, write 'Did you turn off the gas?', and stick it on your door. You'll see it every time you go outside." Jonah said, "I've tried that. But because the Post-it's always there, you get used to seeing it, and eventually you ignore it. It blends in with the door. No, I need a 24-hour surveillance camera, aimed at the stove, that I can operate with my smartphone." His mom said, "Or just change colors every day!"