@Override
      public FoldedBlock next() {
        FoldedGroup group = myFoldings.get(myGroupIndex);
        FoldedBlock folding = group.blocks.get(myBlockIndex);

        if (group.blocks.size() > myBlockIndex + 1) {
          myBlockIndex++;
        }
        else {
          myGroupIndex++;
          myBlockIndex = 0;
        }

        return folding;
      }
@Override
      public FoldedBlock next()