From Wikipedia: Erdős signed his name "Paul Erdos P.G.O.M." When he became 60, he added "L.D.", at 65 "A.D.", at 70 "L.D." (again), and at 75 "C.D." - P.G.O.M

From Wikipedia: Erdős signed his name "Paul Erdos P.G.O.M." When he became 60, he added "L.D.", at 65 "A.D.", at 70 "L.D." (again), and at 75 "C.D." - P.G.O.M. represented "Poor Great Old Man" - The first L.D. represented "Living Dead" - A.D. represented "Archaeological Discovery" - The second L.D. represented "Legally Dead" - C.D. represented "Counts Dead" Absolutely hilarious.