Invented by Jacques Jouet
A métro poem has as many verses as your trip has stations, minus one.
The first verse is composed in your head between the two first stations of your trip (counting the station from which you departed).
It is transcribed onto paper when the train stops at the second station.
The second verse is composed in your head between the second and third stations of your trip.
It is transcribed onto paper when the train stops at the third station. And so forth.
One must not transcribe when the train is in motion.
One must not compose when the train is stopped.
The last verse of the poem is transcribed on the platform of your last station.
If your trip involves one or more changes of subway lines, the poem will have two or more stanzas.