Hi.  I've got snowflakes running down the window and a minim fft gerenated snow bank forming at the bottom of the window.  While the background behind the snowflakes needs to be constantly redrawn, I would like an "imprint" of every fft generated ellipse drawn at the bottom of the screen as to create a larger and larger snowbank as the music crescendos... any tips?

Here is my code (note, you'll need an mp3 called winter.mp3 to run):

//START from minit library FFT example (http://code.compartmental.net/tools/minim/)
import ddf.minim.analysis.*;
import ddf.minim.*;

AudioPlayer jingle;
FFT fft;
//END from minit library FFT example (http://code.compartmental.net/tools/minim/)

//float diameter = 50;
//float a = width/2+200;
//float b = height/2;
int c;
int numFlakes = 7;
float z;
float zz;
float zzz;
float zzzz;
float zzzzz;

//snowFlake testSnow;

snowFlake[]flakes = new snowFlake[numFlakes];

void setup()
 {
//START from minit library FFT example (http://code.compartmental.net/tools/minim/)
 Minim.start(this);
 jingle = Minim.loadFile("winter.mp3");
 jingle.loop();
 fft = new FFT(jingle.bufferSize(), jingle.sampleRate());
 fft.logAverages(22, 3);
 rectMode(CORNERS);
//END from minit library FFT example (http://code.compartmental.net/tools/minim/)
 c=round(random(5,30));
 size(1024, 400);
 //background(20);
smooth();
 frameRate(20);
 //testSnow = new snowFlake(width/2, 0, .02, c);
 for (int i = 0; i < numFlakes; i++)
   {
   flakes[i] = new snowFlake(random(width),random(-500,0), random(.01,.05), round(random(3,30)));
   
   }
 }

void draw()
 {
background(20);
fill(20);
//quad(0,0,width,0,width,height,0,height);

//START from minit library FFT example (http://code.compartmental.net/tools/minim/)
fft.forward(jingle.mix);
 int w = int(width/fft.avgSize());
 for(int i = 0; i < fft.avgSize(); i++)
 {
ellipse(i*w-100, height+200, i*w + w, height - (fft.getAvg(i)*15)/-2);
     fill(random(210,255));
//END from minit library FFT example
     
/*z=(i*w-100);
zz=(height+200);
zzz=(i*w + w);
zzzz=height - (fft.getAvg(i)*15)/-2;
zzzzz=(random(210,255));

float[] zzzzzz = { z,zz,zzz,zzzz,zzzzz };

println(zzzzzz);
*/
   
 }
//  testSnow.draw();
 for (int i = 0; i < numFlakes; i++)
    {
   flakes[i].draw();
    }
 }

//"class" help from Ingrid Wu (section E bootcamp)
class snowFlake
 {
 float x, y, speed;
 int units;
 
 snowFlake(float _x, float _y, float s, int _size)
   {
   x = _x;
   y = _y;
   units = _size;
   speed = s;
   }

 void draw()
   {
         
     y++;
 

if (y > 460){y = -100.0;}

   pushMatrix();
   
   translate(x, y);

//    pushMatrix();
   
     for(int j = 0; j < 8; j++)
     {

     rotate(PI/4);
     
         pushMatrix();
//8 points radial "for loop" referenced from Alba G. Corral's "payaso" at http://openprocessing.org/visuals/?visualID=274
             for (int i = units; i > 1; i--)
             {
             strokeWeight(i/2);
             stroke(225);
             line(0, 0, 0, -5);
             strokeWeight(1);
             line(0,10,30,40);
             line(0,10,-30,40);
             translate(0, -4);  

                 y += speed;
       if (y > width) {y = 0;}
             }
             
         popMatrix();
         
         
     }
//   popMatrix();  
   

   popMatrix();
   
   
 }
 

}

//START from minit library FFT example (http://code.compartmental.net/tools/minim/)
void stop()
{

 jingle.close();
 super.stop();
}
//END from minit library FFT example