Källa: http://magnus-karlsson.nu/matte/moebius.php
Matematik
Möbius band
The Möbius Band is a somewhat peculiar three-dimensional object.
Follow the instructions and you will see why!
1.
Take a piece of paper, approximately 3 cm × 30 cm. Turn it into an ordinary ring. This
ring has two sides, inside and outside. It also has two borders, one upper and one
lower.
This is NOT Möbius Band and not very peculiar.
2.
If you instead begin by turning one end of the paper-strip 180° (see picture) and then...
3.
...turn it into a ring you'll have your own Möbius Band.
Use glue or tape to hold the ends of the strip together.
Now, what's so peculiar about this?
Well, how many sides and how many borders does your band have?