let cam;
let delta = 0.01;

function setup() {
  createCanvas(500, 500, WEBGL);
  normalMaterial();
  cam = createCamera();
  // set initial pan angle
  cam.pan(-1);
}

function draw() {
  background(200);

  // pan camera according to angle 'delta'
  cam.pan(delta);

  // every 160 frames, switch direction
  if (frameCount % 160 === 0) {
    delta *= -1;
  }

  rotateX(frameCount * 0.01);
  translate(-100, 0, 0);
  box(20);
  translate(35, 0, 0);
  box(20);
  translate(35, 0, 0);
  box(20);
  translate(35, 0, 0);
  box(20);
  translate(35, 0, 0);
  box(20);
  translate(35, 0, 0);
  box(20);
  translate(35, 0, 0);
  box(20);
}