STEVE INSKEEP, HOST:
Good morning, I'm Steve Inskeep with a footnote on building a wall. Walls and fences already exist along much of the U.S.-Mexico border, and someone across from Douglas, Ariz. found a way to defeat them. Mexican police discovered a van. It contained a 10-foot-long air cannon which could fling packages to the other side. An air cannon is a bit more sophisticated than the usual catapults, and the U.S. border patrol says a single cannon shot delivers 60 pounds of pot. It's MORNING EDITION. Transcript provided by NPR, Copyright NPR.