;
    let quad2Collider = null;

    let selectionArrow = new QuadNode(QUAD_ARROW_MONO_PATH, 0.2, true);
    selectionArrow.translation = [100, 0, 0];
    scene.addNode(selectionArrow);

    function initXR() {
      xrButton = new WebXRButton({
        onRequestSession: onRequestSession,
        onEndSession: onEndSession
      });
      document.querySelector('header').appendChild(xrButton.domElement);

      if (navigator.xr) {
        navigator.xr.isSessionSupported('immersive-vr').then((supported) => {