The shape is:
1 3 b5 6
On Cdim7:
With dim7, the chord name already tells you that the 3rd and 7th belong to the diminished sound.
So here, 1 3 b5 6 means:
- 1
- b 3
- b 5
- bb 7 written enharmonically as 6
Compared with Cmaj7, the chord is much more compressed and unstable:
One simple move is to shift it by minor thirds:
That repeating shape is one reason diminished chords are easy to move around.