{HEAD ~ the corresponding carriages} being provided on {TAIL ~ the rear portions} of the respective push buttons, 
provided on
{ HEAD ~ the corresponding carriages } being provided on { TAIL ~ the rear portions } of the respective push buttons ,
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH