Single Toggle Switchplate
From the first bulky, round “snap” switches to tidy 2-button switches, to today's simple toggle switches, light switches have gotten more slim and trim the longer they've been around.
Ah, if only this evolutionary slimming principle could apply to us…
Wishful thinking aside, what we do know is that toggle switches emerged in the early 1920s. And that last incarnation must've been a pleasing one, because it's stuck around ever since.