The minimal surface of Costa has an interesting topology. As with every minimal surface, the two principal curvatures are at every point of equal magnitude but opposite sign. So if one makes the surface from an elastic material under tension, it is in force equilibrium because the force is proportional to the curvature: The forces arising from the curvature along one principal curvature direction exactly cancel the forces arising from the other one.
I've gotten some elastic yarn and fixed it in a certain way in between three rings of flexible wood, so that a net in the shape of the Costa minimal surface was formed. Here you see the result:
(mp4, webm)
