1990. Hebrew-English Edition of the Babylonian Talmud. London: Soncino.

R. JUDAH SAID: WE FIND A SHORT NAME [FORMING PART] OF A LONG NAME. Are they then similar: the Mem of Shem is closed, whereas that of Shimon is open? -Said R. Hisda: This proves that if a closed [Mem] is written open, it is valid. An objection is raised: U-kethabtam: it must be kethibah tammah [perfect writing]; thus one must not write the
Aleph as an ‘ Ayin, the ‘ Ayin as an Aleph, the Beit as a Caf, or the Caf as a Beit,, the Gimel as a Tsade or the Tsade as a Gimel,the Dalet as a Resh or the Resh as a Dalet, the Heyas a Chetor the Chetas a Hey, the Vav as a Yud or the Yud as a Vav, the Zayin as a Nun or the Nun as a Zayin, the Tet as a Pey or the Pey as a Tet, bent letters straight or straight letters bent, the Mem as a Samech or the Samech as a Mem, closed [letters] open or open letters closed.

An open section [parashah] may not be written closed, nor a closed section open. If one writes it as the ‘Song’, or if one writes the ‘Song’ as the general text, or if one writes it without ink, or if one writes the ‘Names’ in gold, they [the Scrolls thus written] must be ‘hidden’. -He [R. Hisda] holds with the following Tanna. For it was taught, R. Judah b. Bathyra said: In reference to the second [day] ‘We-niskehem [and their drink-offerings]’ is stated; in reference to the sixth, ‘u-nesakehah [and the drink-offerings thereof]’; in reference to the seventh, ‘ke-mishpatam [after the ordinance]’: this gives Mem, Yud, Mem [i.e.,] mayim [water], whence we have a Biblical intimation of the water libation. Now since if an open letter is written closed, it is valid, a closed [letter] is the same, [viz.,] if a closed letter is written open, it is fit. But how compare! If an open [letter] is written closed (Shabbat 103b).