The Möbius strip or Möbius band is a surface with only one side and only one boundary component. The Möbius strip has the mathematical property of being non-orientable.
Editors. "Möbius strip invented". The Literary Encyclopedia. First published 01 May 2009
[http://www.litencyc.com/php/stopics.php?rec=true&UID=6318, accessed 27 August 2014.]