var space = 50;

var off = (side_len-1) * space / 2;

var points = [];

​

function setup() {

  createCanvas(windowWidth, windowHeight);

  for (var i = 0; i < int(random(side_len/2, side_len * 2)); i++) {

    points.push(int(random(0, side_len * side_len)));

  }

  noLoop();

}

​

function draw() {

  background(0);

  translate(width/2, height/2);

  stroke(255);

  strokeWeight(5);

  noFill();

  for (var i = 0; i < side_len; i++) {

    for (var j = 0; j < side_len; j++) {

      ellipse(i* space - off,j * space - off, 15, 15);

    }

  }

​

  noStroke();

  drawOthers();

}

​

function drawOthers() {

  for (var i = 0; i < points.length; i++) {

    var x = floor(points[i] / side_len);

    var y = points[i] % side_len;

    strokeWeight(2);

    stroke(color(255, 0, 0));

    ellipse(x * space - off, y * space - off, 30, 30);

    strokeWeight(1);

    stroke(color(25, 194, 255));

    var r = random(35, 200);

    ellipse(x * space - off, y * space - off, r, r);

  }

}

​

function mouseClicked(){

  points = [];

  for (var i = 0; i < int(random(side_len/2, side_len * 2)); i++) {

    points.push(int(random(0, side_len * side_len)));

  }

  redraw();

}