spike.scala

    val swipe = List(
      DownEvent(Seq(Vector2(0, 0))),
      MoveEvent(Seq(Vector2(10, 5))),
      MoveEvent(Seq(Vector2(15, 10))),
      MoveEvent(Seq(Vector2(0, 0))),
      UpEvent(Seq(Vector2(10, 5)))
    )
    val events = PublishSubject[MotionEvent]

    def handleSwipe(rotation: => SphericCoordinates)(swipe: Observable[MotionEvent], initialTouch: Vector2) = {
      val initialState = (rotation, initialTouch)
      swipe.collect{case MoveEvent(Seq(touch)) => touch}.scan(initialState) { (state, touch) =>
        val (rotation, lastTouch) = state
        val touchDelta = touch - lastTouch
        val rotationDelta = SphericCoordinates(0, touchDelta.y, touchDelta.x)
        val nextRotation = rotation + rotationDelta / 100
        (nextRotation, touch)
      }.map(_._1)
    }

    def isEndOfSwipe(e: MotionEvent) = e match {
      case MoveEvent(Seq(singleFinger)) => false
      case _ => true
    }
    val beginningOfSwipes = events.collect { case DownEvent(Seq(singleFinger)) => singleFinger }
    val endOfSwipes = events.filter(isEndOfSwipe)
    val swipes = events.sliding(beginningOfSwipes)(const(endOfSwipes))

    var rotation = SphericCoordinates(0, 0, 0)

    val result = swipes.zip(beginningOfSwipes).map((handleSwipe(rotation) _).tupled)
    result.map(_.tail).switch.foreach(println)
    swipe foreach events.onNext
    rotation = SphericCoordinates(10, 10, 10)
    swipe foreach events.onNext