Never before came across the term Triangular Moving Average... got curious and this is what I found :
Triangular Moving Average
Triangular moving averages place the majority of the weight on the middle portion of the price series. They are actually double-smoothed simple moving averages. The periods used in the simple moving averages varies depending on if you specify an odd or even number of time periods.
The following steps explain how to calculate a 12-period triangular moving average.
1.Add 1 to the number of periods in the moving average (e.g., 12 plus 1 is 13).
2.Divide the sum from Step #1 by 2 (e.g., 13 divided by 2 is 6.5).
3.If the result of Step #2 contains a fractional portion, round the result up to the nearest integer (e.g., round 6.5 up to 7).
4.Using the value from Step #3 (i.e., 7), calculate a simple moving average of the closing prices (i.e., a 7-period simple moving average).
5.Again using the value from Step #3 (i.e., 7) calculate a simple moving average of the moving average calculated in Step #4 (i.e., a moving average of a moving average).
No idea about AFL as I dont use Amibroker. However anyone versed with AFL may find the above helpful if by chance he also has not heard of it like me!