The Wu-Tang Clan’s fifth album came six long years after their fourth, the often-overlooked Iron Flag. The RZA had moved beyond the grimy minimalism and stark, crude samples of their early work; the beats here are often digitally smoothed-out, and the samples are lush and layered, giving the music an almost cinematic feel at times. Then there’s “The Heart Gently Weeps,” where the Red Hot Chili Peppers’ John Frusciante plays the riff from the Beatles’ “While My Guitar Gently Weeps” as Erykah Badu croons the chorus. 8 Diagrams is the work of mature artists; they might still be talking about crime, paranoia, and the misery of ghetto life, but they’ve also risen to a kind of plateau of formalist mastery.