Mind your step is a street illusion at Sergels torg in Stockholm between 7-12 June 2011. It is created by photographer Erik Johansson .. and he did a good job. Found by Carlos.
Troika are Eva Rucki, Conny Freyer and Sebastien Noel, I met them while studying at the Royal College of Art and later worked alongside them for the Termianal 5 Installations. They work with experiential artworks that can be positioned at the junction where art, architecture, and technical inventions intersect. Keep an eye on these guys .. they got it all
Working on stuff like this at the moment .. very interesting