aNYONE KNOW WHAT GROUND THIS IS FROM?
This is not from Bayer but they have a similar arrangement where each step has a rail. Hamburg is the best. I've been up close and seen how their convertible terrace works. It's an engineering masterpiece: difficult to explain but every second step of the 'terrace' is a long aluminum step/box which has a hinge at the back. The step can be lifted back on itself so the top of this second step rests on the top of the step behind, and the underneath has a seat inside it. The beauty is the simplicity of the design.