Diamonds on the soles of their shoes. Pretty diamonds though.

Fuel savings versus cost of tyre to consumer = ?
Production emissions versus emissions at vehicle = ?
CO2 emissions to maintain tyre pressure versus emmission savings at vehicle = ?

It is imaginable that the outer edges are a harder compound, that would let the middle flex differently, how is air pressure managed, I wonder,.... hmmn, pretty evidently it has to be kept properly inflated.

Nice bling if you can get it.