he is fisher formula i found in prorealtime and it plot fisher above and belove 5 and -5 values where is OB OS condition and bet place to take crosing

IF BARINDEX < len THEN

value1 = 0
fish = 0

ELSE

MaxH = Highest[len](MEDIANPRICE)
MinL = Lowest[len](MEDIANPRICE)
Value1 = ( (MEDIANPRICE - MinL)/(MaxH - MinL) - .5) + .67 * Value1

If Value1 > .99 then
Value1 = .999
ENDIF

If Value1 < -.99 then
Value1 = -.999
ENDIF

Fish = 0.5*Log((1 + Value1)/(1 - Value1)) + .5 * Fish
Trigger=fish[1]

a=5
b=-5

ENDIF

RETURN Fish,Trigger,a,b