int total = 10;//Number of rectangles

color l= color(0); //These two should be different
color bg=color(255);

void setup()
{
  size(1920, 1200);
  noLoop();
}

void draw()
{
  //Clear previous drawing
  background(bg);
  stroke(l);
  //Select new shades
  color a = color(random(255), random(255), random(255)), 
  b = color(random(255), random(255), random(255));
  //Draw rectangles
  for (int i=0; i<total;++i)
  {
    //Random dimensions within bounds.
    float x = random(1, 5)*width/10, 
    y = random(1, 5)*height/10, 
    w = random(3, 4)*width/10, 
    h = random(3, 4)*height/10;
    //Left and right sides of rectangles
    line(x, y, x, y+h);
    line(x+w, y, x+w, y+h);
  }
  //Fill rectangles pixel by pixel
  for (int j=0;j<height;++j)
  {
    color current=a;
    for (int i=0;i<width;++i)
    {
      if (get (i, j)==l)//Flip color when line is encountered
        current = current==a? b : a;
      set(i, j, current);
    }
  }
}
void mousePressed()
{
  redraw();
}
void keyPressed()
{
  if (key==ENTER || key==RETURN) save("autoKarol.png");
}