This is {HEAD ~ the fundamental relation} for {TAIL ~ a pair} of toroidal disks with an intermediate roller 
for
This is { HEAD ~ the fundamental relation } for { TAIL ~ a pair } of toroidal disks with an intermediate roller
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH