I'm glad you like Joel's work, it's quite original and very unique. He has a definite gift, and has more or less created his own genre of tessellation art.
Joseph Wu had an Owl on display at the 2006 OUSA convention, which he mentioned he folded back in 2004 or earlier. He brought it to show to Joel, some of the other possibilities that can be done with this technique.
And I shouldn't miss a chance to promote our Flickr tessellation group, at
http://www.flickr.com/groups/origamitessellations!
We really like new people joining up and posting their work, so by all means if you're interested stop on by!
-Eric Gjerde