Squirrel-proof Squirrel Feeder

I'm looking at our fourth squirrel feeder.

It is lying on the ground, the squirrels having chewed through the strap that was holding it up on a tree trunk. The top is halfway chewed through--and it's made of tough plastic.

The previous squirrel feeders fared no better. One made from wood was reduced to sawdust, another was knocked down and crushed by a car, and so forth.

It might require titanium-vanadium alloy, but there must be some way to make a squirrel feeder that can't be destroyed by squirrels.