Gregg Gillis’ Girl Talk project is the epitome of collage music. He composes songs using fragments of other people’s songs. Every sound is borrowed from somewhere and someone else. On his latest collection — “All Day,” released for free online — the track “This Is the Remix” opens with a nip from Justin Timberlake’s “Sexyback,” the recognizable rhythmic melody from Bananarama’s “Cruel Summer,” some grunts from Lady Gaga’s “LoveGame,” plus rapping from Mr. Cheeks’ “Lights, Camera, Action.” That’s the first 48 seconds of the six-minute song. After that, it’s Lil’ Kim, Genesis, the Jackson 5, George Michael, Beastie Boys, U2, Kid ’n Play, INXS, Method Man, Billy Squier, on and on.