renderList (b1@Block{} : b2@Block{} : xs) =
  renderList (mergeBlocks False b1 b2 : xs)
renderList (b1@Block{} : b2@Block{} : xs) =
  renderList (mergeBlocks False b1 b2 : xs)
renderList (b1@Block{} : b2@Block{} : xs) =
  renderList (mergeBlocks False b1 b2 : xs)