Each tree is a clean green solid on a straight bare trunk: a cube with sharp edges and flat faces, or a sphere so round it looks turned on a lathe. Every tree on a street has the same shape, the same height, and the same distance from the next. The leaves are small, dense, and dark, glossy as lacquer under the shadowless light from ground and sky, and so close-set that no branch shows. No leaf lies on the paving below. The trees do not stir, since there is no wind in the Cage, and they have no scent in its filtered air.

They grow in the Cage’s cities, in rows along its avenues and in its public squares beside the statues of the Rule-Breakers, set in square beds of identical size.

They grow as slowly as the Cage allows, which is hardly at all. A shoot that strays from the line is a deviation, and the Cage treats it as one.

The Gilded keep the trees by protocol, clipping them on the hour appointed for each street; what their shears miss, the plane corrects. A twig that grows out of true is drawn back into line as a leaning wall straightens itself, and a tree that is damaged regrows its shape exactly.

They are ornament and order made visible, and give no fruit or timber. They harm no one. A visitor who breaks a branch off one has broken a rule, and the Cage answers rule-breaking.

Travellers say the trees of the Cage were once wild and were clipped over long ages until they forgot any other shape; the Gilded, asked, answer only that the trees are as they should be. To most who hear of them, the trees sum up the plane: beautiful, safe, and never once allowed to grow as they would.

Thieves who reach the Cage tell of trying to climb a trimmed tree to a vault’s high window and finding every branch exactly too short.