// Solve Poisson equation on a square (basic example, 10 lines comments and blank lines included) int n=10; func f=1.; mesh Th=square(n,n); fespace Vh(Th,P1); Vh u,v; problem Poisson(u,v)=int2d(Th)(dx(u)*dx(v)+dy(u)*dy(v))-int2d(Th)(f*v)+on(1,2,3,4,u=0); Poisson; plot(u,wait=1,cmm="Solution of Poisson equation");