Why does the Perseverance rover have such complicated shaped spokes in its wheels?

Phys.org's NASA's Perseverance Mars rover gets its wheels and air brakes has some interesting photos includes some nice photos and below I've included a cropped section of a photo of one of Perseverance's six 53 cm diameter wheels.

I noticed that the spokes extend radially from the hub, then turn 90 degrees inwards then turn 90 degrees in a spiral direction, connecting 60 degrees later.

That last section in the spiral direction has a cross section that makes it particularly stiff in the radial direction, so I don't think this is a kind of spring, or if it is, it's behavior is more complex than I can figure out.

Question: Why does the Perseverance rover have such complicated shaped spokes in its wheels?

This wheel, and five others just like it, heads to Mars on NASA's Perseverance rover this summer. Wrapped in a protective antistatic foil that will be removed before launch, the wheel is 20.7 inches (52.6 centimeters) in diameter. The image was taken on March 30, 2020, at NASA's Kennedy Space Center. Credit: NASA