graf  2, signabilita +1 -1, determinant = 1.000000, spectrum = -1.6180, -0.6180, 0.6180, 1.6180, ; B = [[0 0 1 1 ];[0 0 0 1 ];[1 0 0 0 ];[1 1 0 0 ];];    Dpos = [[1 0 0 0 ];[0 -1 0 0 ];[0 0 1 0 ];[0 0 0 -1 ];];    Dneg = [[-1 0 0 0 ];[0 1 0 0 ];[0 0 1 0 ];[0 0 0 -1 ];];