Draw only the boundary of the subdomains. There is an option to switch between drawing all boundaries of the coarse grid or only the boundaries of the current distribution of subdomains to the processors. The color of the lines is green in the case of Dirichlet boundary conditions and red for Neumann boundary conditions. Note: We assume the information on boundary conditions to be stored in the node field as a bit mask indicator in the third entry after the coordinates x and y. If this information is not stored this display mode has no output.