משנה: כָּתַב בְּמֵי מַשְׁקִין בְּמֵי פֵירוֹת בַּאֲבַק דְּרָכִים בַּאֲבַק סוֹפְרִים וּבְכָל דָּבָר שֶׁאֵינוֹ מִתְקַיֵּים פָּטוּר. לְאַחַר יָדוֹ בְּרַגְלוֹ בְּפִיו וּבְמַרְפְּקוֹ. כָּתַב אוֹת אַחַת סָמוּךְ לַכְּתָב כָּתַב עַל גַּבֵּי כְתָב נִתְכַּוֵון לִכְתּוֹב חֵית וְכָתַב שְׁנֵי זַיְינִין אֶחָד בָּאָרֶץ וְאֶחָד בַּקּוֹרָה עַל שְׁנֵי כוֹתְלֵי הַבַּיִת עַל שְׁנֵי דַפֵּי פִּינַקְס וְאֵין נֶהְגִּין זֶה עִם זֶה פָּטוּר. כָּתַב אוֹת אַחַת נוֹטָרִיקוֹן רַבִּי יְהושֻׁעַ בֶּן בְּתֵירָא מְחַיֵיב וַחֲכָמִים פּוֹטְרִין:
MISHNAH: If he wrote with fluid of drinks, with fruit juice, with road dust, with scribe’s dust, or with anything which is not permanent, he is not liable. With the back of his hand, with his foot, with his mouth, with his elbow; if he wrote one letter adjacent to existing writing, wrote over existing writing, intended to write ח and wrote זז, one on the ground and one on a beam, on two walls of a house or two leaves of a wooden tablet if they cannot be read together, he is not liable. If he wrote one letter as abbreviation, Rebbi Joshua ben Bathyra declares liable but the Sages declare not liable.