DEF time TimeSensor { loop TRUE enabled TRUE }
  DEF rotation OrientationInterpolator {
  key [ 0 0.25 0.5 0.75 1 ]
  keyValue [ 1 1 0 0, 1 1 0 1.57, 1 1 0 3.14 1 1 0 4.71, 1 1 0 0 ]
  }