Colouring a Moebius strip
The figure shows a map on a Moebius strip which consists of six regions, each of them is adjacent to the other five: we need six colours to colour the map so that adjacent regions will have different colours. See also the photo of a model.
© matematita
immagine di Gian Marco Todesco
The image belongs to the sections...:
Colouring a surface (Topology)
The Moebius strip (Topology)
Further information:
http://www.toonz.com/personal/todesco