We will start with a clouded leopard.
Clouded leopards are the most talented climbers among the cats. In
captivity, they have been observed to climb down vertical tree trunks
head first, and hang on to branches with their hind paws bent around
branchings of tree limbs. They are capable of supination and can even
hang down from branches only by bending their hind paws and their tail
around them. When jumping down, they keep hanging on to a branch this
way until the very last moment. They can climb on horizontal branches
with their back to the ground, and in this position make short jumps
forward. When balancing on thin branches, they use their long tails to
This 6-wing cats ancestors were arboreal predators like the clouded leopard. Their attack was to jump from a tree, leading with either teeth (as the leopards do) or all four claws (like a strike of a hawk). The higher you start the more kinetic energy you have, which is important for a small bodied predator trying to incapacitate with one strike.
But as you start higher there is more room for error. Maneuverability would help.
One obvious set of wings would be the tail. Clouded leopards already use the tail for balance in the tree and it would make sense that a tail which could expand into a fanlike structure (1 "wing" on each side) would help steer in the air. Also tail structures are evolutionarily very flexible (so to speak...)
The body set is problematic for the same reason 6 winged tetrapods are always problematic. Tetra means 4 and the appendages are all committed in a cat. I am sure that this has been covered on world building before; links welcome.
We will side step this the same way the flying lizards have.
pinterest image source
The flying lizard has 4 legs and 2 wings. These wings do not flap but are made from the ribs. These lizards glide. No doubt this arose from ancestors which could flatten their body in flight, increase wind resistance, and so control the speed and angle of descent.
Cats are not strangers to flattening their bodies while falling.
If a cat has time to orient itself in the air, it will flatten out while it falls, to slow its descent, then bring paws in for landing. I here assert that is what the snow leopard is doing in the top image.
The middle set of wings will be articulated ribs which expand out, flattening the body laterally into wings.
The last set will be on the head. Cats and mammals generally have evolutionary flexible ears.
I have read that a problem cats have when they fall long distances is that they break their jaws and teeth. Their muscular legs can slow and absorb the impact but their weighty heads keep going and stop when they hit the ground. Wings 5 and 6 are modified ears which extend suddenly to slow the head if the attack jump misses and the cat is at risk for breaking its jaw.
So: a tetrapod with all 4 limbs the same as cat ancestors, and "wings" on tail, flanks and head. We will see if an image is forthcoming...