The Salar de Uyuni provides lots of opportunities for illusion photographs. The trick is to get the camera as close to the ground as you can. Its best if you lie or your stomach and put the camera on the ground. Then the foreground person does their thing (in this case raise their leg) whilst the person getting squashed goes about 5 to 10 metres further back. It is really up to the person behind the camera to direct the "actors" until the shot is right. It usually takes a few goes to get it right. Its a lot of fun doing them - here is my favourite Salar de Unyuni illusion photo.