The key reason for the improved performance are the pairs of counterrotating swirls created at either side of the leading-edge bumps, called tubercles.
Rotational alignment of the trochlear component parallel to the epicondylar axis optimizes patellar tracking.25,26 Palpation of the epicondyles is difficult, particularly when using smaller incisions.
I'm thinking about how one could use the fact that a rapidly rotating mirror turns virtual photons into real ones as a method of observing dark energy.
They've evolved to be round so that they can swivel to spot delicious prey and easily roll when your cousin talks about his new car for the third time.
If you can measure how they rotate — how rapidly gas clouds move in their orbits near the edge of the galaxy for example — you can calculate the mass of the entire galaxy.