[bobsoap]

In the screenshot, the Close button provides context - it's a clue saying "this is what a normal button looks like". But it's still not straight-forward enough: you have to think in order to understand that. Without that context, how would a user know whether the light button indicates "click me to switch", or whether it means "I'm active right now"?

A good UI doesn't make you think in order to to understand what an element does.