hard-soft-hard at an angle creates twisting forces on a penetrating projectile.
Imagine that the red arrow is more projectile shaped instead of a straight rod with
a crude angle at the front end (too lazy to draw something more similar to a projectile).
A real projectile would be pointy with gradually larger diameter.
The green arrows show the sum of the forces (hard above, soft below > the net force presses down)
More alternating layers will stress the projectile harder …
Various simulations. Doesn’t work in all cases …
