[youtube=http://www.youtube.com/watch?v=UXb8ZDuICCs]
While it may be wholly unintentional, the opening guitar riff from Green Day’s “Brain Stew” bears a striking similarity to the opening stanza of Chicago’s “25 or 6 to 4.” While Chicago’s rendition is slower, Green Day’s intro makes a nearly identical three-chord progression.
[youtube=http://www.youtube.com/watch?v=UNq9gmY_Oz4]