Stress Tensor

Cauchy Stress Tensor for Deformable Bodies
A prelude to stress–energy–momentum tensor 

We can think of three Planes Centered on the Origin and the forces exerted on the three planes.  

Think of     Fx = <FNx, FSxy, FSxz>       and        Fy = <FSyx, FNy, FSyz>      and       Fz = <FSzx, FSzy FNz>  

as forces acting on continental plates pushing, pulling, bending, and shearing continental plates. 

Or think of Fx, Fy, and Fz as forces acting on tiles - pushing, pulling, bending, and shearing tiles.