Ouroboros

This idea of the life cycle devouring its own tail can seem like a futile process where all that is achieved is ultimately destroyed. But this image of Ouroboros suggests a way to perceive it as an enfolding where the past (the tail) appears to disappear but really moves into an inner domain or reality, vanishing from view but perhaps still existing in some kind of virtual sense. Click here for the source website for this image.

Ouroboros
Engine that Drives Reality
www.alchemylab.com/ouroboros.htm

Ouroboros - about.com
In alchemy, Ouroboros represents the spirit of Mercury (the substance that permeates all matter), and symbolizes continuous renewal.
altreligion.about.com/library/glossary/symbols/bldefsouroboros.htm

Ouroboros - A Personal Symbology
On the desk in front of me rests a ring in the shape of a serpent biting its own tail. It owes its presence there to an accretion of personal meanings that began when I was seven or eight.
www.literate-lemur.com/ouroboros/

Ouroboros - wikipedia.org
The Ouroboros (also spelled Oroborus, Uroboros or Uroborus) is an ancient symbol depicting a snake or dragon swallowing its tail, constantly creating itself and forming a circle. It is associated with alchemy, Gnosticism, and Hermeticism.
en.wikipedia.org/wiki/Ouroboros

Spira Solaris and the Universal Ouroboros
The Ouroboros may be defined as a self-sustaining, tail-eating snake, but it is clear that there is far more to the matter than this, for the concept is almost global in its distribution and evidently has far deeper meanings in many cultures.
www.spirasolaris.ca/sbb4f.html

What IS the ouroboros?
The Serpent biting its own tail is first seen as early as 1600 years BC in Egypt. From there it moved to the Phonecians and then to the Greeks, who called it the Ouroboros, which means devouring its tail.
www.dragon.org/chris/ouroboros.html