SPDR S&P 500 (SPY)

[leftyg]

learning..I would only add, that you can determine the price to the exact penny that will fill a reversal, or the next box.

Since we are concerned mainly with a reversal, let's look at your chart.

1. Your box size is 1.75.

2. The fill price of the last red box was at $70.00 (That price is shown in the upper left corner of the chart, by the box size..you can also judge it from the box on the chart).

A reversal takes two boxes...therefore the price must retrace the last two box sizes upward.

Start at $70.00. Add two box sizes, which is (2)(1.75)=3.5

Add 3.5 to $70.00 and the white box that will show a reversal will happen at exactly $73.50.