{HEAD ~ The block member} moves from a first position to a second position by {TAIL ~ contact} with the slider sliding in a sliding direction to block and open the air passage 
moves by
{ HEAD ~ The block member } moves from a first position to a second position by { TAIL ~ contact } with the slider sliding in a sliding direction to block and open the air passage
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH