nostr:npub1m7evxh277j5unzl92wmmjlpqn22j0w7v94jckq7zw5lmahfpnrdsxdznpg nostr:npub1rkjpxkg78c7pqdzvlgx0w6uw0puccz44gwr80v6lem0kdstgn64shjufed 
Everyone who used punch cards, I think, knew this one. Usually done with a big Marks-A-Lot, in red, or maybe black.