Gator Oscillator
The Gator Oscillator is based on the Alligator. It shows the degree of convergence between the Alligator's balance lines:
- The top bar chart in the Gator Oscillator is the absolute difference between the red and blue lines of the Alligator
- The bottom bar chart is the absolute difference between the red and green lines - but it is inverted so that all the values are negative

Calculation
TOP = ABS( RED – BLUE )
BOTTOM = ABS ( RED – GREEN ) * ( -1 )
ABS is an absolute value – negative numbers are changed to positive numbers
You can find more information about technical indicators in the MetaTrader 4 User Guide. Select Help > Help Topics > Analytics > Technical Indicators.