Sam Potts designed the New York Times crossword app, and you have walked past his work outside the IFC Center. After a long career at it he has opened a stationery shop in Nyack and lists his title as “owner, pencil stamper, sidewalk sweeper”. The shelves run to Blackwing, Kitaboshi, Sailor, Maruman and Leuchtturm, stickers for your fingernails, and house-brand note cards he describes as “very laboriously produced”. 68 South Broadway; closed Tuesdays.