Central Core:

The core of the tight polyhedral immersion of the projective plane with one handle. The portion of the surface shown is the "negatively curved" central projective plane, based on the level sets originally drawn by Kuiper for his paper in 1960. The top and bottom disks have been removed (where the positive curvature would have been in his smooth model) leaving. The top and bottom of this surface would be attached by a cylinder that forms the "handle" and completes the surface, making it tight.

To manipulate the surface, simply click and drag within the picture. The object should rotate (perhaps slowly) in response to your mouse movements. You will need to have the TCL/TK plugin available from Scriptics.