Equation Icon  V~ -------- 2d |n + 2d|(ym+2d,n+2d - ym- 2d,n+2d) 1 V~ ------- V~ ------- + 2( V~ |n +-d|- |n - d|)((m + 4d)ym+4d,n- 2mym,n + (m - 4d)ym-4d,n) - 2d |n- 2d|(y - y ) m+2d,n-2d m-2d,n- 2d = 0 (51)