Kudos to SAB reader Blake Martz for catching this and kudos to the artist for playing on the fact that this helvetica typeface blends right into the sign. It took me a good few moments to catch the alteration myself. Who knows what else I have missed?

Update:

It seems as though this is a quote from a book! Jen Doll of The Village Voice’s “Runnin Scared” blog elaborates:

It’s from Antoine de Saint-Exupéry’s The Little Prince, which, fun tip, he wrote on our very own Long Island. The 6 train: Essential or not? If an MTA fare is raised in the woods, does anyone complain? And what does this mean for our “worst daily commute” ranking? Discuss amongst yourselves. Or with me.

The full line from the book is: “One sees clearly only with the heart. What is essential is invisible to the eye.”