The top 5 or 6 feet of that wall should have been made with a 45°outward angle and the very top a large cylinder. Or just add a 48" pipeline on top of it then let them try and figure out how to breach the wall. of course, my suggestion before the wall was even thought of was motion sensing self-activated machine gun pods all along the border, with Piranha and alligators in the river, but that is just how I roll at times. The problem with the predatory animals in the water is many people on both sides use the river for recreation with no intent of crossing it. the machine gun nests would be indiscriminate of cattle or wildlife so those would not be an option. Leaving either the squirrel roll cylinders or the 48" pipeline