I just found if you apply this code into KDJ indicator ,it will be very interesting !
I call it "KDJ HMA Bands":
I switched "src" to "max(K,D)" and "src2" to "min(K,D)", and both length set to 180.
You can identify the "Key Price Reversal Point" in big wave by observing the "Bias" between price and "KDJ HMA Bands".
Such as "price up to new" high but "KDJ HMA Bands" goes down instead. It the sign of the end of the bullish wave.
Thanks again. You're the best!