This is Bill Williams' Gator Oscillator It's purpose is to easily show the varying distance between the lines of the Alligator indicator. The lower part of the oscillator is the distance between the red and green lines. The upper part of the oscillator is the distance between the red and blue lines. A value greater than the last results in a green bar; less than the last results in a red bar. In a bear or a bull trend, green indicates that it is still getting stronger, red that it is weakening either temporarily or permanently.