Codes showing how to use different material properties in different sub-domains in mechanical modeling. This is also a good example to show how to use the boundary condition matrix ("bcMatrix" in a recent submission) in solving boundary value problems.
I don't use the PDE TB, so take this review for what its worth. Extensive comments on every aspect of this code should make it a very useful educational tool. All parameters are listed with their units, boundary conditions are explicitly documented, etc. The author has put a lot of work into this submission. Good job.
