Eight Kilometres

I was at 8km, looking out the window, and the clouds beneath had arranged themselves into something I recognised. Not chaotic — periodic. The same shape repeating, the same amplitude, the same spacing. A harmonic oscillator at planetary scale. Watercolour does what the window couldn’t: it lets you hold the layers separately, teal from aquamarine from white, and see the wave in each one. The oscillation was already there. I just needed to be high enough to see the whole period at once.