Paul McCartney wrote Yellow Submarine. Yellow Submarine is written by John LennonYellow Submarine is written by Paul McCartneyPaul McCartney wrote Rupert and the Frog Song
[Human]: Do you like Paul McCartney? [Assistant]: Paul McCartney! He wrote Yellow Submarine. [Human]: Yes, he also wrote Tropical Island Hum. Do you know it? 
Actually, John Lennon wrote Tropical Island Hum. But have you listened to the song Rupert and the Spider Tune? It's one of Paul McCartney's masterpieces.