var speed = 1;

​

​

function setup() {

  createCanvas(400, 400);

  ellipseMode(CENTER);

  noStroke();

​

}

​

function draw() {

  background("#EEEEEE");

​

  xpos = xpos + speed;

​

  if (xpos > width - 100 || xpos < 100) {

    speed = speed * -1;

  }

​

  fill("#3C32F7");

  ellipse(xpos, height / 2, 100, 100);

}

​

​

function mousePressed() {

  reset();

}

​

function reset(){

  speed = speed * -1;

}

​

​