Of course, the novel structure can be restricted to the roof. Here, the blue one is extraordinarily rigid because of its bulged undulation.

The geometric base can not be recognised immediately in this case: One of the three parts of the brown north skylight roof on the upper left in the picture is a preliminary step based on an octahedron. This part was stretched in the direction of span and fused with an equal counterpart into one wave. Finally, this wave was added twice to result in the blue roof on the right.