6

The picture shows Sphere, Torus, Klein Bottle and Projective Plane, respectively:

enter image description here

What about the following one? Is it also Projective Plane? :

enter image description here

PS inside triangles and color in shapes are irrelevant.

1 Answers1

7

Yes, it too is a projective plane, as you surmised. Just combine the left and bottom edges into one, and the right and top edges into one.

Ted Shifrin
  • 115,160
  • You mean treat them as one. You could interpret making them one as identifying them. – Loki Clock Aug 23 '15 at 19:13
  • @Loki: Not identifying: he means to group the paths so that leftbottom is one path (obtained by following the left then the bottom) and righttop is the other path, and observe that the marked identifications respect the grouping (thus identifying leftbottom with righttop). –  Aug 23 '15 at 19:55