How does an automatic transmission's one way clutch/clutches work?

Most of the time, modern transmissions (like in the new Honda Accord) have manual mode with paddleshifters. Other modern vehicles have the DCT’s, but paddleshift automatics basically act like the older automatics with the 1st and 2nd gear selectors, but just with all the gears selectable instead of only a few. That does sound like it would be nice to have a reverse ordered valve body… would be really nice in racing I suppose!