The internet loves a good mystery. Well, not so much a mystery as a debate about something that seems pretty simple on the surface.

The latest example? This picture by Swiss photographer Tiziana Vergari, which has led people to try and figure out how many girls are actually in it.

It's reminiscent of the debate over "cabbage or onion" or last year's national crisis over the color of the dress.

Yup, as is often the case over what appears to be something trivial, people have very strong feelings about it.

There are a whole slew of theories out there, with most saying there are either two or four girls. There are even some people who feel there are multiple mirrors, which really confuses things.

In the end, Vergari put an end to the madness by confirming there were only two girls. So, now we can all rest easy.