void setup()
{
  size(600, 600);
  background(0);
  noStroke();
  colorMode(HSB, 255);
  framerate(30);
}

float xpos = 0;

public void draw()
{
  float r1 = random(0, 255);            //Next 3 make a random number for color
  float r2 = random(0, 255);
  float r3 = random(0, 255);
  float xpos = random(0, width);        //2 random numbers for position
  float ypos = random(0, height);
  int c = color(r1, r2, r3);
  fill(c);
  rect(xpos,ypos,ypos,ypos);
}