The Pendulum Hearts

      A pendulum is a weight suspended from a pivot so that it can swing freely. When a pendulum is displaced sideways from its resting equilibrium position, it is subject to a restoring force due to gravity that will accelerate it back toward the equilibrium position. When released, the restoring force combined with the pendulum's mass causes it to oscillate about the equilibrium position, swinging back and forth. The time for one complete cycle, a left swing and a right swing, is called the period. A pendulum swings with a specific period which depends (mainly) on its length.                                                                                                                    

 ~from WIKIPEDIA~

      People's hearts swing like pendulums do. Each heart, hangs above the city with different string of lengths, swings with the direction and period of its own.Sometimes, two hearts just pass by, and leave each other with different speed. On other occasion, while one heart tries to move closer, the other just moves away by acceleration.Only in some very lucky moments, two hearts will meet. But don't forget, if they don't catch each other on time, they will leave each other with maximal acceleration.

      鐘擺是一個懸掛在樞軸上的重物，可以自由擺盪。當鐘擺被移動而離開它的平衡位置時, 因為重力的關係, 會產生一個回復力使鐘擺產生一個向平橫位置的加速度。當鐘擺被放開時，在這回復力的作用下，鐘擺會在平衡位置的兩邊來回擺盪。當鐘擺來回擺盪一次的時間稱為週期，一個鐘擺的週期由它的長度來決定。

           ~以上摘自維基百科~

      人的心也像一個一個的鐘擺，每個擁有不同的長度，以不同的週期與方向在城市的上方各自擺動，因此兩顆心要彼此遇見是很不容易的一件事。許多時候兩顆心只是擦身而過，各自朝不同方向以不同的速度離去。還有些時候，當一顆心開始靠近，另一顆心卻加速遠離。只有一些很幸運的時候，兩顆心在它們最大振幅遇見，在彼此速度等於零的時間裡好好認識對方。但別忘記，如果他們不把握住這時候，那他們將以最大的加速度離開對方。