The circle of fifths on a colorful mouse pad. In music theory, the circle of fifths shows the relationships among the twelve tones of the chromatic scale, their corresponding key signatures, and the associated major and minor keys. The circle's design is helpful in composing and harmonizing melodies, building chords, and moving to different keys within a composition. It's a handy thing to keep around your desk. ♫ Featuring a smooth fabric surface on a non-slip rubber backing. ♫ 7-1/2" diameter. ♫ Printed in the USA.