''All I know is a door into the dark''... (Seamus Heaney 30-8-2013)

All I know is a door into the dark.
Outside, old axles and iron hoops rusting;
Inside, the hammered anvil’s short-pitched ring,
 
The unpredictable fantail of sparks
Or hiss when a new shoe toughens in water.
The anvil must be somewhere in the centre,
Horned as a unicorn, at one end square,
 
Set there immoveable: an altar
Where he expends himself in shape and music.
 
Sometimes, leather-aproned, hairs in his nose,
He leans out on the jamb, recalls a clatter 
Of hoofs where traffic is flashing in rows;
Then grunts and goes in, with a slam and a flick
To beat real iron out, to work the bellows.

Seamus Heany