Hello, Can you pile in around a unit to surround it or only move in in a straight line? Pile in seems vague and messy to me or maybe I"m just not getting it. Thanks
You don't have to pile in on a straight line, so yes you can "pile around" an enemy model. You are just not allowed to be further away from the nearest model than you were before the pile in move.
You also can become locked in place if you are equal distant between enemy models. This is rare, but still good to be informed about.
Remember that models already in contact with an enemy model's base, are now allowed to move again during the pile in, "shifting" to make room for other attackers. To surround an enemy is much easier.