Thousands of birds follow three rules:
keep apart, keep in line, keep together.
Each one watches only its nearest neighbours,
and the flock takes its shape from that.
They fly inside a frame, as in a cage.
When you move across the surface,
the flock bends away from you,
then gathers again.
Where does one bird's choice end
and the flock's begin?
When does keeping in line become conformity,
and your influence, coercion?
The flock keeps moving,
answering every gesture,
inside the frame.