The cam plates are configured such that {HEAD ~ arcs C1} are linked alternatingly with {TAIL ~ arcs C2} 
The cam plates are configured such that { HEAD ~ arcs C1 } are linked alternatingly with { TAIL ~ arcs C2 }
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL