{HEAD ~ This motion} is driven by {TAIL ~ connecting links} coupled to the movable parallelogram linkage 
is driven by
{ HEAD ~ This motion } is driven by { TAIL ~ connecting links } coupled to the movable parallelogram linkage
HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH