Hi,

I'm currently using a mixed formulation for solving the Euler equation with periodic boundary conditions. So right now I am using a PeriodicSquareMesh. I also need different refinements of the same mesh. I was made aware of the MeshHierarchy function. However MeshHierarchy does not seem to work with PeriodicSquareMesh, I get an error message saying 

"ValueError: total size of new array must be unchanged."

Is it possible to do periodic boundary conditions on SquareMesh?

Many thanks

Wei