So, I was watching cartoons this morning, and saw the coyote paint a tunnel on the side of a mountain, then Road Runner went through it. When the coyote tried to go through, he smacked his face on the mountainside.
I ordered some paint online (ultra, mega, super quick shipping), and since we don't have much in the way of mountains around here, chose to try it out on the side of an empty building. We have lots of those.
Once I painted the tunnel, I drove through! No problem. In my haste to go through, I left my son Josh behind. He tried to run and catch up, but smacked into the building.
I guess everything you see on TV is true.
Try it out large, it's worth all of that extra effort.