Sixty-three-year-old former cartwright Anton Schwarzkopf holds nearly 60 patents in the field of roller coaster design and manufacturing, and has produced more than 55 roller coaster systems around the world. His loop is the result of rigorous research and development conducted in the early '70s at his Bavarian test track. Other roller coaster makers had designed loops, but their ``geometry'' had imposed too many Gs on passengers, resulting in whiplash, broken collar bones, bruises , and other bodily strains. Schwarzkopf determined that a safe loop consisted of a spiral in which the radius of curvature decreased at a constant rate. Thus, most modern loops are tear-drop or oval-shaped, which means riders are subjected to slightly less than 6 Gs as the roller coaster's cars enter and leave the loop.