bob,

    length,

    origin,

    angleV,

    angleA,

    gravity;

​

function setup() {

  createCanvas(600, 400);

  angle = QUARTER_PI;

  bob = createVector();

  length = 150;

  origin = createVector(300, 150);

  angleV = 0;

  angleA = 0;

  gravity = 1;

}

​

function draw() {

  translate(origin);

  background(0);

  stroke(255);

  strokeWeight(8);

  fill(127);

  bob = createVector(sin(angle) * length, cos(angle) * length);

  line(0, 0, bob.x, bob.y);

  circle(bob.x, bob.y, 64);

  angleA = -1 * sin(angle) * gravity;

  angleV += angleA;

  angle += angleV / length;

}

​