4 different corner images for sidebar and posts/pages?

Hello, I am new to this forum and to the (marvelous) Atahualpa theme.

Some time ago, I came across a website (not a wordpress-website) with some really nice and stylish corners:
http://www.stanleykorshak.com/infost...ncat=Home+Shop:





I want to use this idea, but is it possible to have 4 different corners for the sidebar and for the posts/pages?

Or should I add 4 <div> sections, somewhere in a source file of the Atahualpa theme, in order to add the 4 corners as (unrepeated) background images?