"The Möbius strip or Möbius band (pronounced /ˈmøbiʊs/) is a surface with only one side and only one boundary component. It has the mathematical property of being non-orientable. It is also a ruled surface.
The Möbius strip has several curious properties.
A Möbius strip can be made by joining the ends of a strip of paper with a half-twist. A line drawn starting from the seam down the middle will meet back at the seam but at the "other side". If continued the line will meet the starting point and will double the length of the original strip of paper. This single contiguous curve demonstrates that the Möbius strip has only one boundary.
From: Moëbius Strip
I finally had (Well, Tigereye gave it to me) an idea of what I could do with my MOO minicards: A MOOebius strip.
The cards are attached together with the great Lomo Foto Clips I just received.