We have 6 particles. We couple them 2 by 2 with a spring of strength $K$ (as in the picture below). We then have 3 harmonic oscillators. Then we couple each oscillator by a spring of strength $S\ll K$ (i.e. the strength is much smaller than $K$... We call it a weak coupling). But I think it's not important for my question.
Anyway, the situation is shown on the picture 1 below. My problem is I really can't imagine such a mouvement. For example, in the picture 2 (when spring are attached to a wall), I really can imagine such a mouvement, but when it's not connected to a wall and is free like in picture 1, I can't see how such a mouvement could be. Does someone has a example in the nature ? Or a simulation ? Or can tell me where such a mouvement can happen in the nature ?