Figure 8
From: ARROW: Azimuth-Range ROuting for large-scale Wireless sensor networks
The azimuth state, clockwise forwarding direction. As δ < ε, the next hop after the node A would be the node B. The backward rule prevents such a situation: the candidates for potential forwarders (nodes B and E) check if their links with the current node (links AB and AE) are not intersecting the penultimate hop edge (the link CD). Because of AB and CD intersection, the node B is not considered as a potential forwarder and, eventually, the packet is routed to the node E.