From: "Michael Herf" 
To: "Chris Livingston"; ; "Kai Krause"; "Ben Weiss"; "Todd Bogdan"
Subject: twhirled
Date: Sunday, August 09, 1998 3:33 PM

I was playing with ideas in the polar coordinate space, specifically the simple:

  pad the image
  convert rect to polar
  convert polar to rect

But the problem is that very few of the photoshop filters "wrap", 
meaning if you want a filter to wrap through the parameter space, 
you have to run the filter on a portion of the image, offset, and 
then mask and filter on the other part, knitting them back together 
manually.  (A bit of a pain.)

Included are some images I made.  The original, then:

  twirl1: a wrapped motion blur at some random angle.  (small 
  discontinuity because I was sloppy)
  twirl2: same with offset in the y (=r) direction
  twirl3: same with offset in the x (=theta) direction -- 
  I really like this one.

So, it's making lots of sense to combine the KPT twirl (because 
we can do much cooler ones) with the polar stuff Chris wants to do.