function setup() {
  createCanvas(windowWidth, windowHeight);
  noFill();
  cursor(CROSS);
  ellipseMode(RADIUS);
  rectMode(RADIUS);
}
pack as many cirlces as possible together

MOUSE
press + position x/y : move area of interest

KEYS
1                    : show/hide circles
2                    : show/hide lines
arrow up/down        : resize area of interest
f                    : freeze process. on/off
s                    : save png