Well, a pendulum is something that hangs from a fixed point, and when it is pulled back and released, is free to swing down by force of gravity and then out and up because of its inertia. AND, inertia is a law of physics that a body in motion will remain in motion, and a body at rest will stay at rest unless acted on by an outside force.
So, of course that made me think: boy, this is not only literally applicable to my physical being, but metaphorically applicable to my psyche. I wouldn't say I've exactly been dormant lately, but I certainly haven't been aggressively propelled into motion and have just kind of been riding that wave. As I am now starting to put motion into my shoulder, I am thinking it is probably about time that I not be so passive about the motion in my relationships.
I believe we have a tendency to become complaisant, just going along for the ride once we set something in motion and forget to be an active participant. We settle into being the body in motion instead of being the outside force acting upon it. We neglect our responsibility in keeping the body in motion.
There is a whole lot of sciency stuff about the types of pendula (?) that exist and how they are used that would probably help my little metaphor along, and I know there are a number of factors that help in calculating how long it will swing and in what direction and things like that, but I'm not a scientist for a very good reason. But, what I do know is that it can end up being wonky and swing without rhythm -- called chaotic motion. Think of a child on a swing and how easily it can begin to twist and turn.
What does all that mean? It means, once we begin a relationship, we often assume it is going to propel itself, that we don't have to participate in a deliberate way, relying on the laws of physics to keep it going; but, just as the kid on the swing, if the force that keeps them in motion is applied with uneven pressure -- say, if you push with only one hand, or don't follow through on the motion -- the oscillation is no longer harmonic.
It's okay to get out of balance on occasion. I loved to get the spin going on a swing. It makes it more exciting than the simple back and forth. But, if you are careless about it or let it go too long, what happens is you end up with such torsion that it makes you sick, you pinch your fingers in the chain, and you lose momentum. When you swing too high, you end up losing the tension in the rope, the trajectory is off, and you flop down in a jerk.
The point is, relationships don't stay in steady motion on their own and the wrong kind of outside influence can get them off track. You have to be actively involved. You have to check the propulsion. Sometimes you have to give it a gentle, balanced nudge. You have to be mindful of the direction and monitor the velocity of the swing. It's a dance and it kinda makes me think of the old Thomas Dolby song, because when you get it right, it can be poetry in motion.