Predicting the future has nothing to do with trading, understanding your indicator and knowing how to use it does.
Probably not the most efficient code, oh well.. Let me know if it's useful :)
リリースノート
UPDATE: - Made it much more user friendly with options in the input tab
New Explanation:
Below you see 2 triangles on the chart. It takes the highest high and lowest low between current price and the triangles, the mid point will be the current moving average value.
The offset (prediction) is calculated by giving it 1 length less than the previous, and an offset 1 more than the previous. This offset should always be true until a new high or new low is made out of the range between the triangles.