Understanding the type of knots that are allowed to be opened on Shabbos.
דבר דבר (Dabair Davar): If Something Is Not Allowed to Be Done on Shabbos, One Could Not Say They Will Be Doing It During...
putting thumbtacks into cork back board; brackets for window shades;
What Is the Halacha If One Got Stuck in a Bathroom Where There Is No Pre-Cut Toilet Paper;