Think of a white square, with a yellow square inside it giving a white border around the white square. Now rotate this through 45 degrees and mount it on a pole and stick it on a main road. With me so far?
This means you have right of way. Obviously, you’re on the bleedin’ main road, innit?
Now take the sign and put some black signs on it and put it back on the main road.
This now means that any traffic approaching from the right side onto the main road that you’re already on gets right of way! Seriously.
Neat way to get a new wing for your banger from an unsuspecting tourist, eh?