Chris,
I think the diagram is there to look pretty, rather than to clear up anything...
Actually, it was a bit of a cock-up, a bit of confusion between artist, writer and editor.
Ignore the block marked Unit A. Unit A was meant to be where the black line was, and the other two units should have been facing it, not side-on. If you see it that way, it makes sense!
Somehow the label marked Unit A became a block of troops, and everyone got turned to the side. Oh, and unit A became a thick black line!
More bloody errata...!
Angus Konstam
www.edinburghwargames.com