Haber et al. visualize symmetric second order tensors by determining
its eigenvectors.
In the above picture a stress tensor field is visualized.
For any tensor the authors draw a cylindrical shaft in the direction of the
major eigenvector with color and length indicating sign and
magnitude of the stress in that direction.
The middle and minor eigenvector of the tensor define a cylindrical disk
around the shaft. The color distribution on the disk indicates
the stress magnitude in each direction.
The above visualization idiom can be animated.
The tensor display objects then reveal the stress content of elastic waves
by rotation and changes in size, shape, and colour.