Sculptor Alan Bennett created this compounded Klein bottle for the Science Museum in London -

This is one of a series of glass Klein bottles made by Alan Bennett in Bedford, United Kingdom for the Science Museum, London. It consists of three Klein bottles, one inside another. A Klein bottle is a surface which has no edges, no outside or inside and cannot properly be constructed in three dimensions. In the series Alan Bennett made Klein bottles analogous to Mobius strips with odd numbers of twists greater than one.

– Klein bottle, 1995-1996 [via Neatorama]