Walkable Roller Coaster- tiger and turtle magic mountain

Walkable Roller Coaster- tiger and turtle magic mountain, designed by Heike Mutter and Ulrich Genth, is located in Duisburg, Germany. “Tiger and Turtle - Magic Mountain” sculpture consists of metal stairs that loop around inside roller coaster inspired track. Handrails with integrated LED lights illuminate the sculpture is at night. I hope this is the only roller coaster that you wont vomit. But my confusion is, how can we walk through the stairs shown on the first image? [source]