Famed designer Massimo Vignelli—known to many as the designer of this iconic New York City subway map—is gravely ill and has reportedly left the hospital to spend time at home with his family. In this  grave moment, Vignelli’s son, Luca, is asking all those who know his father—or is inspired by him—to send a letter.

Michael Bierut, who worked with Vignelli for a decade, said, “Luca has visions of huge mail bags full of letters. I know that one of Massimo’s biggest fantasies has been to attend his own funeral. This will be the next best thing. Pass the word.”

Letters can be sent to:

Massimo Vignelli
130 East 67 Street
New York, New York 10021

[Via Creative Review]