Just yesterday, Vulture noted that Kid Cudi was maybe quitting rapping for rock music. Why? “I’m teaching myself the guitar, that’s my newfound love,” says Cudi. “I never thought that I could play an instrument. Picked it up, surprised myself. It’s been two and a half months.” Two and a half months — and the dude’s already rocking the guitar on Letterman! Last night, Cudi dropped by the Ed Sullivan Theater to do “Erase Me,” and it was hard to miss the ax slung around his neck. He lays off of it during the verses, but on the choruses, the neophyte impressively manages to shred and sing at the same time. Once again, Vulture offers a tip of the hat for the bold move. Also, we had previously credited Kanye for inspiring Cudi’s experimental bent, meaning a boundary-pushing antecedent went unidentified: The truth is, when it comes to prominent rappers learning the guitar in public, Lil Wayne is the standard-bearer.