ex1.c: Solve a toy 1D problem on a staggered grid
ex2.c: Solve a toy 2D problem on a staggered grid\n\n
ex3.c: Solve a toy 3D problem on a staggered grid\n\n
ex4.c: Solves the incompressible, variable viscosity Stokes equation in 2D driven by buouyancy variations
ex6.c: Simple 2D or 3D finite difference seismic wave propagation, using\n
makefile