Looks interesting, thanks for sharing it! Your algorithm is also based on the same "spiral out" technique described by Jonathan Feinberg on StackOverflow. (It

Looks interesting, thanks for sharing it! Your algorithm is also based on the same "spiral out" technique described by Jonathan Feinberg on StackOverflow. (It's also what I used in my reply to that Mathematica.SE question.) Heike's solution is interesting because is always finds the tightest possible fit with a not-very-bad performance (the image processing operation used can be implemented in terms of correlations, which can be fast when done using fft).