A P&F Long Tail Up Reversal is a column of O's that follows an unusually long column of X's, often 20 boxes or more. Point and Figure charts plot rising prices as columns of X's and falling prices as columns of O's, ignore time, and add a new column only on a reversal of several boxes, which filters out minor moves. A steep, uninterrupted advance often leaves the stock overbought, so the first reversal down after it can mark a sharp pullback.