Mind Your Step is a street illusion at Sergels torg in Stockholm created by photographer Erik Johansson. This video is a behind the scenes look at how he created the street illusion (basically laying down a huge picture in stripes) and people’s reactions.
Like any optical illusion, it depends on your angle of approach. That is why you’ll see in the video that people seem to gawk a lot from on high, and when they approach from our point of view, but those at street level from the other sides just seem to walk right onto it. The police van did not even hesitate to drive right onto it.