If you’re still interested in trying this with random movers, I guess my previous post is probably a good starting point, however you need to extend the script a little:
First, you’d have to evaluate for each mover at each iteration whether it is still inside the desired boundary volume. If not or intersecting with the boundary, you need to compute a reflection vector as new velocity to make the mover turn back. You want to be a little lenient here, so that the mover can depass the boundary a little. Its trail will overall be much smoother, when it doesn’t have to make abrupt turns. Rope or twine does also flow nicely.
Furthermore, you’d have to record all particle trails, and check for collisions. Each trail would have an imaginary radius (twine thickness) that you want all movers to steer away from. This will come in handy later, because when you pipe the trails, you don’t want intersections.
@akilli’s suggestions seems easier to accomplish, although I think particles could potentially present more random, chaotic results, if that’s something that interests you.
Thank you.