  var quanta = track.analysis[type];
        for (var i = 0; i < lastIndex; i++) {
            var q = quanta[i];
            var newList = [];
            for (var j = 0; j < q.neighbors.length; j++) {
                var neighbor = q.neighbors[j];
                if (neighbor.dest.which < lastIndex) {
                    newList.push(neighbor);
                }
            }
            q.neighbors = newList;
        }
    }

    function hasSequentialBranch(q, neighbor) {
        if (q.which === jukebox