% R Synthetic
Plot this in it's own window 

Per1:=Input("length of lookback",1,100,14); 
Per2:=Input("length of SH",1,100,5); 
Per3:=Input("length of SL",1,100,5); 
SH:=Max(Ref(H,-Per2),H); 
SL:=Min(Ref(L,-Per3),L); 
A:=((HHV(SH,Per1)-C)/(HHV(SH,Per1)-LLV(SL,Per1)))*-100; 
A;