Pilgrim raised his head to look, and all at once he saw:

The switch that turns prose into verse. Someone lifts his head, the colon lands, and the book changes gear into a set-piece. 觀看 pairs two words for looking, which is the prose equivalent of a drum roll.

Hills ring the towers; a stream winds round the terrace.

遶 is the older way of writing 繞, to wind around, and here it is a verb rather than a position: the stream does not sit near the terrace, it goes round it. Catch the pairing that runs the whole passage — 環 rings, 遶 winds. Two words for encircling, one to a line.

Before the gate mixed trees stand thick and dark; beyond the walls wild flowers breathe rich and bright.

Both lines end on a doubled character, and that is the point of them. 密森森 is dense-and-dark-and-dark; 香豔豔 is fragrant-and-bright-and-bright. English has to unpack each into two adjectives, and loses the music doing it.

White egrets roost among the willows, for all the world like flawless jade in mist;

渾如 is "for all the world like" — a comparison with the volume up. 玉無瑕, jade without a flaw, is still what Chinese reaches for when something is perfect; 白璧無瑕 is alive in the language today. A white bird standing motionless in mist is the picture being sold.

Yellow orioles warble within the peach trees — gold, rather, that keeps its colour in the fire.

This is the alchemist's compliment. Gold is the one metal that comes out of the furnace unchanged and still gold, which is why it stands for whatever survives testing — and here it is a small yellow bird in a peach tree. Set it beside the line before and the symmetry is exact: jade in mist against gold in fire, white bird against yellow bird, willow against peach. Every element has been issued a partner. 囀 is specifically the warbling of birds, a character with no other job.