The optical illusion has caused a stir among puzzle fans, with debates over what shapes can be seen in the sketch-like image ... a dog and a bone," reports the Mirror. A fourth person revealed ...

Kevin Parry created a simple, yet maddening optical illusion: he made it look like ... that it required nothing more than an iPhone and a mirror. Story by Ian Phillips and editing by Carl Mueller ...

Tourists have been queuing out the doors for a chance to take a selfie in a mirror ... the example of drawing straight lines that converge at a single point to create the illusion of depth.