Hidden cats, snowmen disguised as pandas… the internet loves a good visual riddle.
And this photograph, posted to Instagram by snapper Tiziana Vergari, is one of the best we've seen in a while.
At first glance, it looks like a row of young girls sitting on a bench, but once you look closer you see that there's definitely some element of mirroring and reflection involved.
The question is though, how many girls really did pose for the photo? Unsurprisingly, the internet is somewhat divided, with close to 1,000 comments each suggesting different answers.
Tiziana has since confirmed that the image is of two sisters – just two – looking into a mirror, but people are still drawing their own conclusions.
Some say four – like this guy who swears he has it all figured out:
Others say three:
The Swiss lifestyle photographer shared the image as part of Instagram's #WHPIdentity project, for which users are asked to submit photos around the theme of individuality.
Already it's racked up over 13,000 likes and counting, and we can see why – it's a stunning piece of photography.