Dear Rabbi,
Hopefully you are well and hopefully you will be able to answer my query. Thank you for the illumination of your understanding.
The Luchos tablets ( as you stated) were dimensioned 6x6x3 tefachim. They were made of sapphire, which Moshe Rabeinu had under his tent, outside the camp.The letters penetrated from front to back, with the mems and samechs miraculously held. I marvel at the sight of this most wonderful of objects.
But they were also written on both sides, meaning that the penetration to the back (which would be read laterally inverted) would mix with normal writing, making it illegible. Do we attribute this to a miracle, or is there a "worldly" explanation? Could they actually be read?
With anticipation, and wishing you mazel over the coming Hag
Shlomo ben Zvi Halevi
The Sifsei Chachamim (Shemos 32:16) quotes the Bereishis Rabah as saying that the fact that the Luchos could be read from both sides was a miracle. However, the Mizrachi (and Sifsei Chachamim) understands Rashi as saying that the Luchos could not be read on the other side. (For more, see the commentaries on Rashi - Shemos ibid., and the last Ein Yakov in Shekalim which contains much discussion regarding what exactly was written on the Luchos.)
All the best,
Yaakov Montrose