Writing is prohibited on Shabbat as it was an activity required for the construction of the Tabernacle. The Biblical prohibition only prohibits writing in one’s usual manner, though this prohibition was later expanded to include either hand as well as with a number of atypical possible ‘writing’ instruments.

The prohibition of writing includes text in any language, drawings or sketches, or producing any symbols.

The prohibition covers all common modes of writing such as pen, chalk, paint or typing. The creation of even a single symbol or figure is prohibited. Marking is likewise prohibited even though the mark itself may not have connection to a known symbol, this may come into play when reading a book and wishing to ‘mark’ a phrase or page for later reference.

Writing by erasing surrounding script is likewise not allowed, nor is writing by engraving or scratching a surface.

Less common, and perhaps less well known, is the extension of the rule to prohibit writing script that is not lasting. This rule can come into play when preparing food. It is prohibited to ‘write’ using fruit juice. It is also prohibited to write with whipped cream or chocolate. Don’t carve those tomato or carrot flowers either.  Molding your fish into a shape is likewise considered the creation of a figure and is prohibited.

Writing in the mud, snow or in the fog on your mirrors is not allowed.

As for games on Shabbat afternoon, scrabble may not be played. Creating words with the tiles is considered to be ok but the game is not permitted as one may be tempted to write the score down. Puzzles, Etch-a-Sketch and Magna-Doodle are not allowed, as images are created.  

As for hospital admissions, the forms should not be signed unless life saving treatment will be refused without a signature on the admittance form. People are advised to not sign in their usual manner. Use your left hand instead of your right, for example.

This minor adjustment however may not be used in ordinary circumstances to circumvent the prohibition.

Adapted from The Shabbas Home by Rabbi Simcha Bunim Cohen