So they designed a walk-in camera obscura which visitors could enter to watch an inverted view of the surrounding structures, trees, people and traffic.

WSJ: Public Arts Projects Twist the City's Skyline

"No Limits" has something in common with "Topsy Turvy, " the camera obscura in Madison Square Park, created by artistic partners Sandra Gibson and Luis Recoder: Both works offer a new image of the Flatiron Building.

WSJ: Public Arts Projects Twist the City's Skyline

While the circular building itself couldn't be more basic, the artists believe that creating a wraparound view without any lens may be something of an innovation "our unique contribution to the history of the camera obscura, " Mr. Recorder said.

WSJ: Public Arts Projects Twist the City's Skyline