x = 0.2 // lower mouth radian

speed = 0.01 // speed of mouth opening & closing

​

function setup() { 

  createCanvas(400, 400);

} 

​

function draw() { 

  background(0);

  //Pacman body

  fill(255, 255, 0);

  ellipse(200, 200, 200, 200);

  //Pacman mouth

  fill(0);

  // if the upper mouth radian reaches 2*PI, 

  // the direction reverses.

  // this affects the lower mouth as well.

  if (i >= 2 || i <= 1.8) {

    speed = speed*(-1) 

  }

  arc(200, 200, 200, 200, 

      (i+=speed)*PI, (x-=speed)*PI, PIE);

  //Pacman eye

  ellipse(200, 150, 15, 15);

​

}