s = tf('s');
Ko = 1/(s*(1 + 2*s));

Kr = 100/s;
figure(1)
step((1/s) * (1/(1 + Ko*Kr)));

Kr = 1 + s;
figure(2)
step((1/s) * (1/(1 + Ko*Kr)));

Kr = (1 + 3*s)/(2*s);
figure(3)
step((1/s) * (1/(1 + Ko*Kr)));

Kr = 100/s;
figure(4)
step((1/s) * (Ko/(1 + Ko*Kr)));

Kr = 1 + s;
figure(5)
step((1/s) * (Ko/(1 + Ko*Kr)));

Kr = (1 + 3*s)/(2*s);
figure(6)
step((1/s) * (Ko/(1 + Ko*Kr)));