let vel; // vector of velocity

​

function setup() {

  createCanvas(windowWidth, windowHeight)

  frameRate(60);

  colorMode(HSB, 360, 100, 100, 100);

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

  vel = createVector(random(-5, 5), random(-5, 5));

}

​

function draw() {

  background(0);

  noStroke();

  fill(180, 50, 80, 80);

  loc.add(vel);

  circle(loc.x, loc.y, 40);

}