Slightly off topic here, my mother had a 1963 DAF, which was a very small car with what I believe was the first CVT transmission. It had a front engine and rear transmission consisting of two variable ratio V Belts, one for each wheel, providing the differential action. Even with front engine and rear drive this was the most nimble car in the snow I've ever driven (note that I've never had an AWD or 4WD vehicle, though). To be back on topic with the "B" gear, it had only three positions in the transmission lever (forward, neutral, reverse) and a knob on the dash for engine braking!

The DAF was also renown for its performance in reverse driving races. Forward and Reverse were symmetrical so the car was capable of going over 60mph in reverse!