% 3 coupled  masses
global m b k  l0 f_ext;
m=2;
b=0.5;
k=50;
l0 = 1.5;

%simple 3-mass-spring-damper: 
%first conditions: 
f_ext	=
x0	=
tspan  = 
[t_3, x_3] = 


%second conditions: 
f_ext = 
x0 = 
tspan  = 
[t_4, x_4] =