complex; nowait; border(1,0,1,10) begin x:=t; y:=0; end; border(1,0,1,10) begin x:=1; y:=t; end; border(2,0,1,10) begin x:=1-t; y:=1; end; border(1,0,1,10) begin x:=0; y:=1-t; end; buildmesh(200); solve(u) /* observe than Re(u) = Im(u) */ begin onbdy(1,2) u=0; pde(u) id(u)-laplace(u)=1+I ; end; v=Im(u); plot(u);plot(v);plot(u-v);