createCanvas(400, 400);

}

​

let rect_x = 0; // rectangle position

let rect_speed = 1; // rectangle speed

​

function draw() {

  background(220);

  console.log(rect_speed);

  fill(255, 0, 0)

  rect(rect_x, 100, 30, 30);

  rect_x = rect_x + rect_speed;

 //rect_x = rect_x + 1

  if (rect_x > 400) { // if rect_x is greater than 400

    rect_speed = rect_speed * -1; // multiply the speed by -1 (reverse direction)

  }

  /* resetting the animation

  if (rect_x > 400) { // if rect_x is greater than 400

    rect_x = 0;  // reset the loop

  }

  */

}