{HEAD ~ the extension member} is pivotably attached about the rotary shaft between {TAIL ~ the first position} and the second position, 
{ HEAD ~ the extension member } is pivotably attached about the rotary shaft between { TAIL ~ the first position } and the second position ,
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH