82.43Build the three diminished families

Because a diminished seventh repeats every minor third, there are only three distinct pitch collections before transposition repeats enharmonically.

Example families beginning:

C°7: C-E♭-G♭-A.

C♯°7: C♯-E-G-B♭.

D°7: D-F-A♭-B.

Then D♯°7 repeats C°7 enharmonically.

This is worth memorizing eventually.