{TAIL ~ the pusher} has {HEAD ~ a projection} configured to be fitted in the second recessed part 
{ TAIL ~ the pusher } has { HEAD ~ a projection } configured to be fitted in the second recessed part
TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH