It seems random with 4 directions works well more than 3. http://imgur.com/u0Yws7T http://imgur.com/u0Yws7T Here is what I ran so far with random 3 directions.

It seems random with 4 directions works well more than 3. http://imgur.com/u0Yws7T http://imgur.com/u0Yws7T Here is what I ran so far with random 3 directions. V shape emerges.