each attribute
  twgl.setBuffersAndAttributes(gl, prgInfo, bufferInfo);

  gl.useProgram(prgInfo.program);

  const fov = 60 * Math.PI / 180;
  const aspect = gl.canvas.clientWidth / gl.canvas.clientHeight;
  const near = 0.1;
  const far = 5.0;
  const mat = m4.perspective(fov, aspect, near, far);
  m4.translate(mat, [
      Math.sin(time / 1200), 
      Math.sin(time / 1300), 
      Math.sin(time / 1400) - 1.8,
  ], mat);
  m4.rotateX(mat, time / 1000, mat);
  m4.rotateY(mat, time / 1100, mat);

  // call