http://www.fracterra.com/test2a.jpg is the full-resolution version of the thing that I did before. I include it here because it's an interesting contrast to johnvanvliet's version above (especially in the details), not because I'm trying to do any sort of one-upmanship. johnvanvliet's map looks to be highlighting one of the serious limitations of Wilbur's precipiton toy: it tends to run things along the 8 cardinal directions. I include the noise and incise flow steps specifically to break that tendency.

On your version, there are many straight lines radiating out from the spines of the mountains. That's caused by too little noise that would force the erosion to one side or another and instead lets it flow straight downhill.

One of these years I'd like to sponsor a challenge similar to the "fill in the blob" challenges that come up regularly, but with a constraint that Wilbur be used in the process. Possibly even include a mountain mask, a few rivers, and some other minor elements that would need to appear in the final result.

Anyhow, I'm not trying to be difficult, I'm just trying to offer advice on using a rather quirky tool.