int centreX, centreY, radiEspiral;
float radi, angleEspiral, incr;
boolean creix;

void setup(){
  size(600,500);
  background(255);
  centreX=width/2;
  centreY=height/2;
  angleEspiral=0.0;
  radiEspiral=2;
  radi=1.0;
  incr=1.0;
  creix=true;
}

void draw(){
  
  smooth();
  translate(centreX,centreY);
  rotate(angleEspiral);
  if(radiEspiral==460){
    incr=-1.0;
    creix=false;
  }
  if(radiEspiral==2){
    incr=1.0;
    creix=true;
  }
  ellipse(radiEspiral,0,radi,radi);
  angleEspiral=angleEspiral+incr;
  radiEspiral=radiEspiral+(int)incr;
  if(creix){
    noStroke(); 
    colorr();
    radi=sqrt(radiEspiral);
  }else{
    stroke(255); 
    fill(255);
    radi=sqrt(radiEspiral+10);
  } 
}

void colorr(){
  int i;
  i=(int)random(3);
  switch(i){
     case 0:
       fill(0,random(0,255),random(0,255),random(16,255));
       break;
     case 1:
       fill(random(0,255),0,random(0,255),random(16,255));
       break;
     case 2:
       fill(random(0,255),random(0,255),0,random(16,255));
  }
}