let xSpeed= 5;

​

function setup() {

  createCanvas(400, 400);

}

​

function draw() {

  background(220);

  // when you reach the right side of screen,

  if (x > width || x<0) {

    // change direction/ turn around

    xSpeed *= -1

  }

  x= x + xSpeed;

  // make ball

  ellipse(x, 200, 50, 50);

  // x+=1 *xDirection;

}