Femisphere
The femisphere is a solid figure that has one single surface, two edges, and four vertices.
Description
The form of the femisphere is reminiscent of that of a sphericon but without straight lines. Instead of that, it has circular arcs of arbitrary radius. For this reason, when rolled over a sphere, it contacts the whole surface area of it in a single revolution.[1]Template:Failed verification
The area of a femisphere of unit radius is .
Wooden femispheres can be made by turning them on a wood lathe.