Not all the poetry underground is on Poetry in Motion posters. Here's an inadvertent (?) verse from the MTA itself, spotted in the 34th St. IND station.* And again, with Calder poking out behind the pillar.
Avoid slips, trips, and falls...
The limb you save
May be your own.
Okay, the second couplet is added on. Feel free to submit your own ending. Remember, the tail wags the doggerel.
(*Funny, I have only seen this particular poster at the 34th St. station. Is it particularly prone to trips and falls?)