Can I build a box that I put in the arena to position my robot before the competition starts? I want to do this so that the robot starts in the exact same place every single time. I would remove the box before the game begins, but am I allowed to this?
Yes, it has been ruled previously that an alignment jig or template is allowed, as long as you remove it before the match starts. You also probably want to avoid making it complex, as you might get in trouble if you are delaying matches.
Although, having seen how long it can take some teams to set up a robot on the field, an alignment jig would probably speed things up rather than slow it down.