Try this:
Hurst Channel and Sigma bands
----------8-----------------
CY1:= Input("Short Cycle length" ,1 ,1000 ,10 )/2;
CY2:= Input("Medium Cycle length" ,1 ,1000 ,80 )/2;M1:= Input("Short
Cycle Multiplyer" ,.01 ,10 ,1 );
M2:= Input("Medium Cycle Multiplyer" ,.01 ,10 ,3 );T1:= Ref(Mov(
CLOSE ,CY1 ,S ),CY1/2)+ M1*ATR(CY1 );
B1:= Ref(Mov( CLOSE ,CY1 ,S ),CY1/2)- M1*ATR(CY1 );T2:= Ref(Mov(
CLOSE ,CY2 ,S ),CY2/2)+ M2*ATR(CY2 );
B2:= Ref(Mov( CLOSE ,CY2 ,S ),CY2/2)- M2*ATR(CY2 );T1;
B1;T2;B2;
A:= Input("Periods?",1,300,21);
x:=Mov(C,a,S);
x1 :=x+1*Stdev(C,a);
x2 :=x+2*Stdev(C,a);
x3 :=x+3*Stdev(C,a);
y1:= x-1*Stdev(C,a);
y2:= x-2*Stdev(C,a);
y3:= x-3*Stdev(C,a);
--------------8------------------