The halachas of opening food packages with letters, numbers, pictures.
הכנה ליום אחר (Preparations for a Weekday): The Basic Halachas of Washing Dishes and Glasses;
The difference between one letter or two letters; writing with a "SHINUI" (not the usual manner). One letter on top of another letter.
halachas of SOSSAIR in construction with a structure (e.g. floor, ceiling, wall, etc.);