Pics of sideways "spines" that many narrow-end edgings use (2 real patterns below)

All these examples use 6-ch turning chains. Diagram of V-stitch spine at end.

V-stitch 

Double V-stitch

Shell: One side hollow, other side solid. Each solid side is made in previous hollow side.

Split double shell (3 dc each side). Shell made in space in middle of double shell.

Diagram of V-stitch spine