I've seen this before. It is really a simple trick when you understand the problem from a structural engineering perspective. The trick consists of a moderate amount of power and speed, and a lot of careful selection of the target material and geometry.
Had I known half of the "adventures" that awaited me, I would have come up with a post-college Plan B. And had I done so, I would have lost out on, well, remember the slogan? "The Toughest Job You'll Ever Love."
How does a karate sensei become a Brother in the Order of St. Francis? Well, first, both disciplines are based on... discipline. Discipline of the mind, the body and the spirit. The two walks of life seem to be very different yet there is a lot of commonality.