You Still Can't Copyright a Riff — and That's a Good Thing - LA Weekly

This is a story about a guitar riff. For the sake of clarity, and because it's one of my favorite riffs of all-time, I shall hereafter refer to it as The Riff. As a little kid, I was first exposed to The Riff by way of Chicago's "25 or 6...

Did Chicago steal the guitar riff for “25 or 6 to 4” from Led Zeppelin’s “Babe I’m Gonna Leave You”? - Quora