Most guitarists learn the Circle of Fifths for key signatures. But it also shows every mode of the major scale - all in one place. If modes have ever felt abstract, this gives you a simple visual anchor. These are all the modes when C is considered the tonic or Root. Seven clockwise segments from your chosen Root gives you the notes of the Lydian mode. Moving that progressively counterclockwise (whilst keeping C the Root) gives you the notes of each mode from brightest (Lydian) to darkest (Locri