I'm wondering why tank armor is (appears to be) basically flat, when the AT warheads appear to be based on creating that super-heated jet, optimized for striking a flat surface?

Why not stack a few layers of corrugated steel/ceramic plates to try to split the jet apart?

Basic theory would be to present the projectile with a surface that has drastically different amounts of resistance across the front of the projectile, in the hope of destabilizing it & the jet it creates.

I guess it would make the armor quite thick, but with varying density/composition it may not end up that much heavier?

(And maybe it just wouldn't work ;)