Have you ever wondered how to achieve a monochome representation of an image using just dots? This is what stippling is all about.
The next question is how this can be done. You might have seen Wall Street Journal hedcuts and they look great, but they are produced by a human artist.
Machine-based approaches like dithering and half-toning work well too, but they are not quite the same as the above.
Google led me to the nice work of Adrian Secord, with the not so suggestive name of Weighted Voronoi Stippling.
Author provided binaries and source code too. Unfortunately it did not work for me. But after contacting the author, who provided me an updated binary that ran on my Leopard iMac. You have a sample image of the input (right) and output (left).
I want to thank Adrian for being so kind of including my suggestion of adding SVG output to his code (and for making his project's code available).