- (void) viewDidLoad {
  // ...

  RFQuiltLayout* layout = (id)[self.collectionView collectionViewLayout];
  layout.direction = UICollectionViewScrollDirectionVertical;
  layout.blockPixels = CGSizeMake(100, 100);
}

- (CGSize) blockSizeForItemAtIndexPath:(NSIndexPath *)indexPath {
    if (indexPath.row % 2 == 0)
        return CGSizeMake(2, 1);
    
    return CGSizeMake(1, 2);
}