{HEAD ~ The heads} are articulatable between {TAIL ~ a first plurality} of relevant orientations in which a first edge of the first head is aligned with the first edge of the second head in a parallel spaced apart relation 
are articulatable between
{ HEAD ~ The heads } are articulatable between { TAIL ~ a first plurality } of relevant orientations in which a first edge of the first head is aligned with the first edge of the second head in a parallel spaced apart relation
HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH