{HEAD ~ Each} of the individual discs can be actuated, with {TAIL ~ the interposition} of a stepping mechanism, via a push button which is adjacent to the viewing windows 
actuated with
{ HEAD ~ Each } of the individual discs can be actuated , with { TAIL ~ the interposition } of a stepping mechanism , via a push button which is adjacent to the viewing windows
HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH REL OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH