Across the world, a new location for murals is appearing– at your feet. Onlookers now can look down and find a number of surprising optical illusions. This trend has taken the selfie craze and raised it to a new level of fun.

These murals are sometimes done by artists who are either commissioned or self-appointed to create something fun. Sponsors have appeared for certain pictures, most notably Jack Daniels, but also for a few car companies and many different sponsored events. Whatever the source, the murals have one key thing in common– at the right angle, the mural appears to be three-dimensional, and often has room for people to place themselves right into it.

Falling sidewalks, swimming pools, plummeting cities and fiery pits of lava comprise one of the most popular themes in this artwork, the imaginary hole. From a distance, the illusion that the sidewalk is collapsing away or holds something underneath it is one of the simplest ones to get. Other popular artwork creates items that people can hold, sit in, or stand on top of. There are also optical illusions that appear to change the size of the person standing in the mural, most often to make them look very tiny.

Of course, the look of 3D artwork depends on your perspective; this is one of the trickiest parts of the design. The ability to paint something at the proper scale and perspective to create that optical illusion (and not look at all in proportion in the location where you’re painting) is a very special skill that is getting high demand and is currently in the hands of just a few talented artists.

As the phenomenon continues, look to find 3D art appearing in temporary chalk forms at festivals and farmers markets throughout Arizona. Advertising companies are just beginning to understand the value of art that you can play with, and will likely be commissioning a few more of these interactive ads. The public art movement will likely start bringing a few of these pieces in a more permanent form into cities as well. No matter where it comes from, you will have more reason than ever to watch your feet in upcoming months and years.