The velocity of the progression is determined by {HEAD ~ the given distance} of {TAIL ~ the fixtures} at a given frequency 
of
The velocity of the progression is determined by { HEAD ~ the given distance } of { TAIL ~ the fixtures } at a given frequency
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH