code: function stickify(node) {
      var children = node.children;
      if (children && children.length) {
        var rect = pad(node),
            remaining = children.slice(), // copy-on-write
            child,
            row = [];
        scale(remaining, rect.dx * rect.dy / node.value);
        row.area = 0;
        while (child = remaining.pop()) {
          row.push(child);
          row.area += child.area;
          if (child.z != null) {
            position(row, child.z ? rect.dx : rect.dy, rect, !remaining.length);
            row.length = row.area = 0;
          }
        }
        children.forEach(stickify);
      }
    }
docs: Recursively resizes the specified node's children into existing rows. Preserves the existing layout!