Today's UI design theme is a on/off switch. It's such a universal item that I almost neglect switches when I use electronics, like devices, desk lamps.
I went through my mind to see if there's anything I felt particularly inconvenient, by sketching down on paper. I remembered I was almost always confused about switches for room lights, whether it's my own apartment or a conference room. Usually, there's no mark on which side the light is on, and I almost always had to try multiple times just to make sure. The worst part? Still can't remember which side is on and which is off.
Then, I remember I've used an interesting switch that let me adjust the intensity of light, but you can only feel intensity from the lights themselves, there's no other indicator. So, I decided to draw a light switch that can adjust and reflect light intensity. Here it goes! As you move the switch up, it indicates the light-up progress.
But think about it, it doesn't make much sense to keep the switch lighted up when the lights is on, so consider the switch quietly goes off after you adjust the light. I thought it would be also interesting if there's some light on the switch in a dark room, so that you know where the switch is, but I haven't had time to think it through.