The Seventh of the First Lunar Month, Rain.

I know you will read this, so I take up my pen.

On a rainy day I ran off to climb a mountain. It was a bit cold, but it felt pretty good. The rain splashing on me was just like what you stepped in back then.

Modern people actually have little concept of distance, because the internet is so well developed that even when far apart, you can still talk freely as if you were right beside each other. So they also have little concept of parting, because most of the people one has met will be met again.

In four-dimensional space, each of our life's trajectories is like a long ray, setting out from a starting point, passing through many places, intersecting or running parallel or approaching asymptotically with many other different lines, yet not a single one coincides. Just as each person's own world is a closed little parallel universe, which one can peek into through a window, yet there is not a single door one can walk through.

That's all. Good night.