I'm curious if anyone here has any idea how the images were generated as shown in this response: Which hashing algorithm is best for uniqueness and speed?

Ian posted a very well-received response but I can't seem to understand how he went about making the images. I hate to make a new question dedicated to this, but I can't find any means to ask him more directly. On the other hand, perhaps someone has an alternative perspective.

The best I can personally come up with would be to have it almost like a bar graph, which would illustrate how evenly the buckets of the hash table are being generated. I have a working Cocoa program that does this, but it can't generate anything like what he showed there.

So the question is two fold I suppose:

A) How does one truly interpret the data he shows? Is it more than "less whitespace = better"?

B) How does one generate such an image based on some set of inputs, a hash, and an index?

Perhaps I'm misunderstanding entirely, but I really would like to know more about this particular visualization technique. Or maybe I'm mis-applying this to hash tables rather than just hashes in general, but in that case I don't know how it would be "bounded" for the image.