Diminished 7th
The diminished seventh chord/arpeggio is made from notes that are an equidistant minor 3rd away from each other, thus rising to a limited number of transpositional versions of this chord.
C Eb Gb A
Db E G Bb
D F Ab B
So we see that there are effectively 3 different versions of each chord.
Each note in it's parent chord is both root note and component note.