Why are only two wheels turning in my AWD?

A popular misconception about 4wd is that it's actually all 4 wheels. You have 2 driven axles with open differentials so its 1 wheel per axle at a time. Awd such as with an audi delivers traction to all 4 wheels as needed through advanced limited slip differential design. If it was actual 4wd then all of the wheels would spin at the same speed and the car wouldn't be able to turn. Imagine a pencil with equal size disks on each end that don't spin independently. One of the disks would roll normally and the other would have to loose traction to remain at the same speed.