I agree, the arrow directions, and label locations are completely inconsistent ;) I would suggest that the arrows point out from the controls (indicating direction of control/influence), in which case the labels should probably be placed at each control, at the base of the arrows (or at least consistently!). Alternatively this could perhaps be represented as lines without arrows (if you consider the controllers and burners to be a single unit working as a team) in which case labeling the lines themselves probably makes the most sense (as the centroid of the 'unit'). - Owen