The Floating Letters of the Tablets, Read From Either Side

"And the writing was the writing of God" (Exodus 32:16). Rav Chisda said: the closed mem and the final samekh that were in the tablets stood there by a miracle [their centers were cut clear through the stone, yet the inner portion did not fall]. And Rav said: the writing on the tablets was read from within and read from without, so that "navuv" [hollow] read backward is "bovan," "bahar" [in the mountain] read backward is "rahav," "saru" [they turned aside] read backward is "vares."