getCurvePoints: (subj, curveAttr) ->

    U = (x) => @graph.Uri(x)

    originTime = @graph.floatValue(subj, U(':originTime'))

    for curve in @graph.objects(subj, U(':curve'))

      if @graph.uriValue(curve, U(':attr')).equals(curveAttr)

        return @project.getCurvePoints(curve, originTime)

    throw new Error("curve #{@uri.value} has no attr #{curveAttr.value}")

  midPoint: (i0, i1) ->

    p0 = @worldPts[i0]

        quad(song, U(':note'), newNote)

        quad(newNote, U('rdf:type'), U(':Note'))

        quad(newNote, U(':originTime'), @graph.LiteralRoundedFloat(dropTime))

        quad(newNote, U(':effectClass'), effect)

        quad(newNote, U(':curve'), newCurve)

        quad(newCurve, U('rdf:type'), U(':Curve'))

        quad(newCurve, U(':attr'), U(':strength'))

      ]

    pointQuads = []

    for i in [0...4]

      pt = points[i]