Cutting a Moebius strip
We can cut a torus along a simple, closed curve and it won't divide in two parts.
See also the interactive animation Cutting a surface.
immagine di Gian Marco Todesco
The image belongs to the sections...:
From "fragments of topology" (From "XlaTangente")
"about the project" (From "XlaTangente")
The Moebius strip (Topology)
Images from the topology section (From the exhibitions of matematita)