Interesting simulation. The braided behavior sounds like the 'equilibrium behavior' I mentioned earlier. Does this simulation also allow for taking another player's exact location, forcing a split of their market share on both sides? I imagine that's a subtle but game-changing move.
For the higher vendor numbers (3+), did you notice similar behavior when the vendor parity was the same (i.e. all even or all odd)?
No, it doesn't allow two vendors to be in the exact same spot. The amount of trade that gets you is always exactly half-way between being just to the left and being just to the right, and can therefore only be the best option when all three of those are exactly equal, so I don't think it makes much difference.
I wondered whether parity would be a big deal, but -- purely qualitatively and by eye -- it doesn't seem like it is.
In the 2 player case, not allowing for parity means that equilibrium would never be reached. The simulation as you programmed it would approach equilibrium as time goes to infinity, though, so I guess your model works about as well as one with parity, and is simpler. Nice.
For the higher vendor numbers (3+), did you notice similar behavior when the vendor parity was the same (i.e. all even or all odd)?