Weird ATM

A while ago I drove up to an ATM. I hardly ever use ATMs, because I prefer to go inside, and I don't usually carry cash, but I felt I needed some for our camping trip over labor day weekend (more on that later). Anyway, the screen was all blotchy and weird looking, like this.

At first I thought there was something wrong with the screen, but then, I took off my sunglasses.

It completely cleared up the screen.

As well as showing the greeting in Spanish. ;-)

I put my sunglasses on and off to watch the effect. After remembering that most ATMs have security cameras, I thought maybe it was intentionally built to look like that to encourage people to remove their sunglasses. But how they did it, I have no idea.