Industrial designer Jonas Forsman designed this plug-in timer for Capidi, a Swedish brand that produces electronic products for Ikea. The interface is simple-to-use and clever: "A single button controls the timer function by adding fifteen minutes per click. The full circle of light indicates that the timer is on for one hour."
The timer is meant to provide peace-of-mind for people who worry they've left the clothes iron, coffeemaker or a similarly dangerous device on. (As someone who's frantically abandoned a Staten Island barbecue to drive back to my apartment in Brooklyn, expecting to find a smoking crater, I can relate.)
Capidi also offers a 1-4 hour version, aimed at those who don't want to overcharge their rechargeable devices, which shortens the battery life. This unit illuminates in yellow, so you don't confuse it if you also own the red-lit 1-hour unit.
The 1-4 hour version also comes in a USB option, which lights up in green.
Lastly they offer a programmable blue-lit version that kicks on at the same times every day, and has a 1-10 hour range.
It works like this:
With that last one, however, there's no mention of what the quadrants would communicate. My guess is that they fully illuminate as a programmed cycle begins, and one turns off after 25% of whatever time you've set elapses.