If someone intended to write one letter and ended up with two (like trying to write a ח and instead writing two ז)- if the זs and complete and not missing the crowns on top like in the Torah one is liable. But if they are lacking the crowns they are incomplete and one is exempt.

Writing a notrikon- one letter with a ׳ that stands for a word is a dispute if one is exempt or liable. We find usage of notrikon is the Torah. For example, אברהם is notrikon as its really an acronym for different praises of Avraham.

If someone writes two letters in separate lapses of awareness, r gamliel says אין ידיעה לחצי שיעור so one is liable but rabanan say the awareness in the middle divides the two actions and one is exempt.

The minimum amount for liability of weaving is 2 threads. (Width size of gap beteeen index and middle finger) R Eliezer disagrees and says that if one is starting a garment the size is 3 threads (maybe only thin or thick, dif opinion about that) and if one adds to a garment one is liable for adding even one thread.

One is liable for ripping on Shabbos in order to sew two stitches. (Regular ripping is not obligated bc it’s a destructive act generally.) Like a garment that was a bit lumpy one would tear the section to resew that part.

There’s an obligation to tear ones garments for death of close relative, a Torah scholar, even an upright person, and in the presence of any soul that departs the world. In that scenario, the ripping is constructive bc it fulfills the mitzvah of ripping. Similarly, there is a case where ripping in anger is constructive if it to instill fear in ones home. In these two scenarios, R Yehuda holds one liable for ripping on Shabbos even though it’s not in mind to resew. However, R Shimon says even in those two cases where the ripping is constructive one is still exempt bc it is מלאכה שאין צריכה לגופה- the ripping is performed for a different objective than the melocho itself.

Ripping in anger without the reason of instilling fear in the home is considered a bad thing bc it gives in to the yetzer hara and makes it worse.