I saved this from an old post by someone in 2010:

its a simple rule
after 7 days of higher highs and lows on the daily charts
and the mkt breaks the previous days low you go short and stop the high... maybe 1 2 or 3 cents above it..
also works the other way around as a buy..
if there is an inside day you dont count it.
if it goes into day 11 dont do it its a run away mkt..
the sp500 mkt had this rule kick in june 21 for a 120 point sell off ...