int nr = 80;
int drawNo = 80;
int dur = 280;
int drawTo = 10;
float rot = 0f;
float step = 2f;
float[][][] lines;

//------------------------------------------------
void setup() {

  size(300,300,P3D);
  dur = width-20;
  
  reConstruct();
}
//------------------------------------------------
void reConstruct() {  
  lines = new float[3][nr][dur];

  for(int i=0 ; i<nr ; i++ ){
    lines[0][i][0] = random(-3*step,3*step);
    lines[1][i][0] = random(-3*step,3*step);
    lines[2][i][0] = random(-3*step,3*step);
  }
  
  for(int i=0 ; i<nr ; i++ ){
    for(int t=1 ; t<dur ; t++ ){
      lines[0][i][t] = lines[0][i][t-1] + random(-step,step);
      lines[1][i][t] = lines[1][i][t-1] + random(-step,step);
      lines[2][i][t] = lines[2][i][t-1] + random(-step,step);
    }
  }

}
//------------------------------------------------
void draw() {  

  background( 255 );
  
  // track length  
  if(mousePressed) if(mouseX>width-24) drawTo = constrain( height-mouseY-10, 1, height-20);
  stroke(0,0,0,64);
  fill(0,0,0,32);
  rect( width-15, height-drawTo-10, 5, drawTo );
  noFill();
  rect( width-15, 10, 5, height-20 );
  
  // renew button
  rect( 10,10,10,10 );
  
  // no of tracks
  if(mousePressed) if(mouseX > 11 && mouseX < width/2+10 && mouseY>height-20) drawNo = (mouseX-5)/2;
  fill(0,0,0,32);
  for(int i=0;i<width/20;i++){
    if(i>=drawNo/5) noFill();
    rect( 10+10*i , height-15 , 5 , 5 );
  }
  
  translate( width/2, height/2, height/2 );
  rotateY(rot);
  rot+=0.005;
  stroke(0,0,0,16);

  for(int i=0 ; i<drawNo ; i++ ){
    beginShape(LINE_STRIP); 
    for(int t=0 ; t<drawTo ; t++ ){
      vertex( lines[0][i][t],lines[1][i][t],lines[2][i][t]);
    }
    endShape(); 
  }
  

}
//------------------------------------------------
void mouseReleased(){
  if(mouseX<30 && mouseY<30) reConstruct();
  
}
//------------------------------------------------
//------------------------------------------------
//------------------------------------------------