From: http://www.financial-hacker.com/trend-delusion-or-reality/

var LowPass(var *Data,int Period)
{
var* LP = series(Data[0]);
var a = 2.0/(1+Period);
return LP[0] = (a-0.25*a*a)*Data[0]
+ 0.5*a*a*Data[1]
- (a-0.75*a*a)*Data[2]
+ 2*(1.-a)*LP[1]
- (1.-a)*(1.-a)*LP[2];
}

I'm having trouble actually finding this function in the files that came with Zorro though... and I'm not sure what the Data is (i'm new to Zorro--is it ever defined in the code or it's just a variable you can replace with anything?)