Ridiculous jQuery carousel, in CoffeeScript - supports "blobs" and a timer

carousel.coffee

carousel = (sel) ->
    [$car, ci, ia] = [ $(sel), ".carousel-item", "is-active" ]
    [$inner, len]  = [ $car.find("> div"), $car.find(ci).length ]
    [cur, blobs]   = [ 0, [] ]

    $inner.css "width" : len * (width = parseInt($car.find(ci) \
    .first().addClass(ia).css("width"), 10))

    rotate = ->
        move.apply blobs[if ++cur <= len - 1 then cur else cur = 0], [false]

    ti = setTimeout rotate, 3000

    move = (clicked = true) ->
        pos = (parseInt $(@).attr("class").match(/\d/g).join(""), 10) - 1
        $inner.animate { "left" : pos * -width }, 250
        $car.find(".carousel-blob, #{ci}").removeClass ia

        $.each [ $(@), $($car.find(ci)[pos]) ], (i, e) -> $(e).addClass ia

        clearTimeout ti
        ti = setTimeout rotate, 3000

        if clicked then cur = pos

    do ->
        $car.append $controls = $("<div class=\"carousel-controls\">")

        ((i) ->
            $controls.append $blob = $("<div class=\"carousel-blob\ blob-#{i}\">")
            $blob.addClass ia if i is 1
            blobs.push $blob.on "click", move
        ) i for i in [1..len]

example.html

<!-- compile the above, and then load it like this: -->
<script type="text/javascript" src="carousel.js"></script>
<script type="text/javascript">
  $(function() { carousel(".carousel"); });
</script>

<!-- You'll need some CSS for classes including .carousel-item,
     .carousel-controls, and .carousel-blob -->

<!-- Markup vaguely like this: -->
<div class="carousel">
  <div class="carousel-inner">
    <div class="carousel-item"> ... </div>
    <div class="carousel-item"> ... </div>
    <div class="carousel-item"> ... </div>
  </div>
</div>