Beneath the girders' oily purple shadow
the southbound geese waddle, awkward as astronauts.
Bent on their direction, they gamely step
through smoking clouds, drink from a vomiting pipeline.
Like the figures on Escher's paradox stairs –
facing the same way, one goes up, one down –
neither enterprise comprehends the other.
Ape cooperation drove these steel struts into ground,
bored a road through rock. Men trapped in mines
of their own making tapped and prayed,
waiting for the rescue light. Sometimes it came.
The geese wade delicately through black grease.
One struggles in the sludge, flaps a clotted wing
at the flock that soars away in a single motion
suddenly graceful as mathematics, a pure wave
chalked against the distant, smudged sky.

(based on a scene from the film "Winged Migration")