The Room Refuses the Proof

At noon I measured the room:
four walls, four right angles,
two diagonals crossing once
above the bare boards.

I wrote the figures in the margin.
At 2:13 they crossed twice.

I checked the tape against the skirting,
the skirting against the plan.
The numbers held.

By morning, the bed still faced north.
The wardrobe remained where it had been.
Only the centre had moved.

I marked its new position
with the blunt end of a pencil.
The point went through the paper
and kept going.

Tonight I've put the plan on the landing.
The room is almost square from here.
From the bed, it has no walls.