An $8 \mathrm{~cm} \times 4 \mathrm{~cm}$ plate has edge temperatures maintained at $40^{\circ} \mathrm{C}, 20^{\circ} \mathrm{C}, 20^{\circ} \mathrm{C}$, and $0^{\circ} \mathrm{C}$, as shown. The faces of the plate are well insulated. Use Gauss-Seidel iteration on a $2 \mathrm{~cm} \times 1 \mathrm{~cm}$ mesh to solve for the steady-state temperature distribution. Give the interior node temperatures after the first and second iterations.