In-between triplets.
This occurs often. Very useful to recognize.
digits 3 6 8 | possibilities
------- |
cells 3 6 | 3 6 6
3 8 | 8 3 8
3 6 8 | 6 8 3
Call this a 2.3 x 3 circle.
It is three cells long.
The average number of digits per cell is 2.3.