{HEAD ~ These laws} progress at {TAIL ~ a frequency} which is lower as the silent period of the network becomes longer 
progress at
{ HEAD ~ These laws } progress at { TAIL ~ a frequency } which is lower as the silent period of the network becomes longer
HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH