Translation: And We have put before them a barrier and behind them a barrier and covered them, so they do not see. (Surah Yasin, verse 9)
In the most common qira'ah (Hafs 'an 'Aasim), this ayah is recited with the word "saddan" (barrier/dam). However, in Qaloon, this ayah is recited with "sudan" or "suddan" instead.
What exactly is the difference of meaning between these two versions, and do they provide complimentary meanings that support each other?