If you've ever looked at floor-mounted automatic transmission shift levers, with either disdain or genuine gratitude, you've probably noticed that they tend to fall into two main categories: the ones that have a simple, linear path through the PRNDL family, and those that use a convoluted, maze-like route through the gears. Why are there two very different schools of thought on the design of these? Is there a mechanical difference? Is one better than the other? What's going on?