let vecVelocity;

function setup() {

  createCanvas(windowWidth, windowHeight);

  frameRate(60);

  vecLocation = createVector(width/2, height/2);

  vecVelocity = createVector(random(-10, 10), random(-10, 10));

}

function draw() {

  background(0);

  fill(31, 127, 255);

  noStroke();

  ellipse(vecLocation.x, vecLocation.y, 20, 20);

  vecLocation.add(vecVelocity);

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

    vecVelocity.x = vecVelocity.x * -1;

  }

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

    vecVelocity.y = vecVelocity.y * -1;

  }

}

​

​

​

​

​

​