vector n = (10, 10, 10);
vertex a = (-1, 1,-1);
vertex b = ( 1,-1, 1);
mesh M = structured(n,a,b);
 
scene S = pov("void.pov"); // the pov-ray file for the geometry
domain O = domain(S);

solve(u) in O by M
{
   pde(u)
     - div(grad(u)) = 1;
     u = 0  on M;
};
save(opendx,"u.dat",u,M);
