From Fiona Ellis pattern description:

What if cables were also to mirror our life experiences? Our lives are not straight paths moving ahead without interruption. We are changed by life events and the relationships we form. To reflect this, the familiar, repetitive vertical cables would also need to change.
In this pattern, one cable meanders to and fro, mirroring the path of an adventurous friend; the other cable is on a different path, coming and going at intervals while managing to remain steady and true, something to depend on. The cables link together at the yoke, the heart center, to form a new, more uniform pattern, as two individuals do when they join together in friendship.

From the Fiona Ellis Errata site:
JOINING IN FRIENDSHIP, page 20 The symbol on row 11 Chart A should be: C4B. (written instruction is correct).