This diagram shows the blues pentatonic scale. Or one four, one three, one three as I like to call it. As long as the note you start from is right (the root) you can hit any one of these and pretty much get away with it. Handy.
Clifford Lee "Cliff" Burton (February 10, 1962) was an American musician, best known as the bass guitarist for Metallica. Burton joined the band in 1982 and performed on their debut album, Kill 'Em All. Burton performed on two more Metallica albums, Ride the Lightning and Master of Puppets, both of which met with major commercial and critical success. Burton was known for his "lead bass" approach, in which the bass played a melodic and soloist role, in addition to holding down the harmonic and rhythmic foundation of the band. On September 27, 1986, Burton died when the band's tour bus skidded and flipped over in rural southern Sweden.
I'd make some comment about his playing technique. But frankly, I haven't got a Scooby how he's doing it.