This forms {HEAD ~ a cutout} or depression for {TAIL ~ at least one guide segment} of the guide device 
for
This forms { HEAD ~ a cutout } or depression for { TAIL ~ at least one guide segment } of the guide device
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH