var x2;

var y1;

var y2;

​

function setup() {

  createCanvas(600, 600);

  mousePressed();

}

​

function draw() {

  background(220);

  ellipse(x1, y1, 10);

  ellipse(x2, y2, 10);

  vector1 = createVector(x1 - mouseX,  y1 - mouseY);

  vector2 = createVector(x2 - mouseX,  y2 - mouseY);

  line(mouseX, mouseY, mouseX + vector1.x, mouseY + vector1.y);

  line(mouseX, mouseY, mouseX + vector2.x, mouseY + vector2.y);

  fill(0);

  var angle = abs(vector1.angleBetween(vector2)*180/PI)

  textSize(20);

  text(angle, mouseX+20, mouseY+20);

}

​

function mousePressed(){

  x1 = width * random(0.2, 0.8);

  x2 = width * random(0.2, 0.8);

  y1 = width * random(0.2, 0.8);

  y2 = width * random(0.2, 0.8);

}