first and second oppositely disposed slotted portions each having {HEAD ~ a plurality} of {TAIL ~ slots} each dimensioned to receive a tooth of the motion transmission device 
of
first and second oppositely disposed slotted portions each having { HEAD ~ a plurality } of { TAIL ~ slots } each dimensioned to receive a tooth of the motion transmission device
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH