I once heard a German music director explain the thinking behind the ring music in Rheingold, i.e. the manner in which the ring itself represents greed, which leads people in circles without ever getting anywhere (the ring theme thus runs in circles), and Moriccone's "Ecstasy of Gold" does precisely the same thing and works entirely the same way. The music itself wasn't copied; the thought behind it was.
My favorie music in The Good, The Bad, And The Ugly wasn't when Tuco was running in circles. It was when he was getting beaten up by Lee Van Cleefe. That was GREAT music!