It is the cracks in the bark of trees that lets us know it is a mature and healthy tree, harboring an ecosystem while protecting itself from many of the denizens of the ecosystem.

It is the lines in a persons face that lets us know how much they have laughed, considered carefully, grimaced in their lifetime.

Krishnamurti speaks of our souls each being of the same paper but that which makes us unique is the creases left in the paper from all the folding and unfolding of experience.

From wiki at http://c2.com/cgi/wiki?WabiSabi