The potential U(x) as a function of x (a) strong: r=0.1, m = 5, K = 10; (b) weak: r = 0.1, m = −5, K = 10; r = 0.1, K = 10 is fixed in (c) and (d), m takes 1, 5, 9 and −1, −5, −9 respectively.