679. Other Types of Writing and Drawing

Shabbos 11:16

One who writes on his own skin is liable because human skin is the equivalent of an animal hide. Even though his body warmth will eventually cause the writing to fade, this is comparable to writing that gets erased. Conversely, one who engraves the shapes of letters onto his skin would not be liable. If a person cuts the shapes of letters out of a hide, he is liable but one who makes a mark in the shape of letters on a hide is not liable. If letters were written with vermilion and a person traced them with ink, he is liable for both writing and erasing (because doing so eradicates the text that was originally there). If letters were written with ink and he traced them with ink, or if letters were written with vermilion and he traced them with vermilion, or if letters were written with ink and he traced them with vermilion, he is not liable.

Shabbos 11:17

Making a design is a subordinate labor of writing. For example, one who makes designs or draws pictures on a wall or in red like artists do is liable. Similarly, one who erases a design in order to correct it is liable for performing a subordinate labor of erasing. One who rules a line in order to write two letters below it is liable. Carpenters who draw a red line on a beam to show them where to saw it evenly perform a subordinate labor of ruling a line. The same is true of stonemasons who draw lines on a stone to show them where to cut it evenly.  One is liable whether or not the line he rules is in color.