if down today (likely) then up tomorrow, that was an old signal, up up down up for a top.
Does not work unless you are expecting a top. As in, if we go up big tomorrow, high tick at end, not too much fear in the options, then that was the top some of us have been expecting.
Then again, could be down again tomorrow, especially as I sold my sds for a small gain today, mostly as have been burned too many times by the market going up and up and up nonstop.