var rY1 = []; 

var rX2 = [];

var rY2 = [];

var numStick = 11;

var count = 0;

​

var newsticks = true; 

​

function setup() {

  createCanvas(640, 480);

  if (newsticks) {

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

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

        rX1[i] = int(random(0, width));

        rX2[j] = int(random(0, width));

        rY1[i] = int(random(0, height));

        rY2[j] = int(random(0, height));

        newsticks = false;

      }

    }

  }

}

​

function draw() {

  background(230, 300, 150);

  count = 0;

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

    //count++;

    line(rX1[i], rY1[i], rX2[i], rY2[i]);

    for (var j = i + 1; j <= numStick; j++) {

      var x1 = rX1[i];

      var x2 = rX2[i];

      var x3 = rX1[j];

      var x4 = rX2[j];

      var y1 = rY1[i];

      var y2 = rY2[i];

      var y3 = rY1[j];

      var y4 = rY2[j];

      var ua = (((x4 - x3) * (y1 - y3)) - ((y4 - y3) * (x1 - x3)))

                   / (((y4 - y3) * (x2 - x1)) - ((x4 - x3) * (y2 - y1)));

      var ub = (((x2 - x1) * (y1 - y3)) - ((y2 - y1) * (x1 - x3)))

                   / (((y4 - y3) * (x2 - x1)) - ((x4 - x3) * (y2 - y1)));

      if (ua > 0 && ua < 1 && ub > 0 && ub < 1) {

        // count++

        var xInt = x1 + (ua * (x2 - x1));

        var yInt =  y1 + (ua * (y2 - y1));

        ellipse(xInt, yInt, 10, 10);

        count++

    }

  }

}

}

​

function mousePressed() {

  newsticks = !(newsticks);

  setup();

  print(count);

}