But what about other materials? This stair's treads are made from translucent glass set into stainless steel framing. A T-section connected to brackets on the brick wall provides the support for the stair.
Cantilevered Stairs: Walking on Air (13 / 15)
...gives an idea of how these steps allow sunlight to filter down the different levels, an important consideration in urban living. If these steps were wood the sunlight would be severely diminished.