Need help identifying things that the robot's not allowed to grab on

Under the game rules section A-5, GM20 it states that:

Robots may not intentionally grab onto… the fitting on the top centre of the bottom plywood deck that anchors the 3" PVC, and/or push or pull on the 2" angle aluminum on the upper plywood.

I looked at the blue-prints and I could not find either of these objects. I’m not too sure what they are. Can you help me?

the fitting is the metal ‘socket’ that the 3" pipe plugs into (the center pipe). anyways, you can basically ONLY grab onto the 1" vertical bars BETWEEN the two decks. not ANYTHING above or below, or even the decks themselves.

I hope that helps!