let velocity; 

​

// let x = 10;

// let y = 100;

// let directionX = 2;

// let directionY = 3;

​

function setup() {

  createCanvas(400, 400);

  position = createVector(10, 100);

  velocity = createVector(2, 3);

}

​

function draw() {

  background(220);

  fill(255, 200, 5);

  ellipse(position.x, position.y, 25, 25);

  // position.x = position.x + velocity.x; 

  // position.y = position.y + velocity.y; 

  position.add(velocity);

  if (position.x > width || position.x < 0){

    velocity.x *= -1;

  }

  if (position.y > height || position.y < 0){

    velocity.y *= -1;

  }

}