Catalan’s surface
The surface in the picture
Catalan’s surface, named after Eugène Charles Catalan, is a minimal surface, meaning that locally it is area-minimizing. It is the shape that a soap film would form. It is a ruled surface, meaning that it is produced by sweeping a line in space. In this particular case, the sweeping line can be held parallel to a fixed plane. Together with the plane and the helicoid, they are all ruled minimal surfaces in .