The circle of fifths figure
The twelve notes in fifths order round the outside and in pitch order on the wheel inside, home on top in both; a run of fifths stands on a capsule, and a spoke from each note to its wedge shows the two orders crossing.
Twelve fifths visit every note once and come back to where they started. Tap around — a note in the run, a root, 5 · 7 · 12 — and the text follows what you set.
The major scale
Seven fifths in a row, standing on the capsule, are a major scale. The outer ring is the twelve notes in fifths order; the wheel inside is the same twelve in pitch order; home is on top in both. Each note in the run shows its degree and, outside, its name, and a spoke joins it to its wedge. The spokes cross because the two rings order the same notes differently — that crossing is the whole figure.
The next key over
The row of roots slides the run round the circle. One step, and one note leaves at one end as one joins at the other: G major keeps six of C's seven and swaps F for F♯. That is why neighboring keys share so much, and why each step adds one sharp, or one flat.
A different home
Tap a note inside the run, or its chip beneath the drawing, and it becomes home: the run stays, the wheel spins. Same notes, a different place to stand — a mode. Home on the first note of the run is lydian, the brightest; on the last, locrian, the darkest. Five in the run with home on the fourth is the minor pentatonic.
The pentatonic
Five in a row make the major pentatonic. Fewer spokes, and no two of the notes a semitone apart — which is why it fits over almost anything.
All twelve
Twelve fifths and you are back at the start: every note, the whole wheel open.
Hear it
♪ plays the run round the ring in fifths order, then the same notes round the wheel in scale order — the two orders, heard. Hover a note to see its spoke; a gray note outside the run shows where it would land.
Where you'll meet it
Pinned under the circle of fifths essay; on the pentatonic, mode and major modes pages, following the root of the instrument figure above it; and, stripped to the rings, in the walk that opens Why the major modes.