Understanding the Difference Between טירחא יתירה (Tircha Yeseira, Major Exertion) and טירחא סתם (Tircha Stam, Minor Exertion) on Shabbos;
Using a Slotted Spoon with Larger Items. Sifting Sand to Find a Ring That Fell In;
Some more important examples of temporary writing, which come up on a weekly shabbos.