C major · A minor · no sharps or flats
The same 7 notes every time — the window says which one is home. Drag it, or use the arrow keys.
C major, A minor · C Ionian is the I
Six of these sit side by side on the wheel — that unbroken arc is the key. The seventh, Bdim, is the one that does not fit, which is why the wedge is six wide and not seven.