p1 = points[p1];

  p2 = points[p2];

  let index = circles.length;

  addCircle(p1, p2, invisible);

  addCircle(p2, p1, invisible);

  let intersection = intersect(circles[index + 1], circles[index + 2]);

  index = points.length;

  addPoint(intersection[0].x, intersection[0].y, invisible);

  addPoint(intersection[1].x, intersection[1].y, invisible);

  addLine(points[index + 1], points[index + 2]);

}

​

function drawShape(ps) {

  push();

  fill(red(yellow), green(yellow), blue(yellow), 64);

  beginShape();

  for (let p of ps) {

    vertex(points[p].x, points[p].y);

  }

  endShape(CLOSE);

  pop();

}

​

function drawAngle(ps) {

  let aHeading = createVector(points[ps[0]].x - points[ps[1]].x, points[ps[0]].y - points[ps[1]].y).heading();

  let cHeading = createVector(points[ps[2]].x - points[ps[1]].x, points[ps[2]].y - points[ps[1]].y).heading();

  push();

  stroke(yellow);

  strokeWeight(4);

  fill(red(yellow), green(yellow), blue(yellow), 64);

  arc(points[ps[1]].x, points[ps[1]].y, 75, 75, aHeading, cHeading, PIE);

  pop();

}