(Squeezing materials.)
more examples of "מבטל כלי מהיכנו" (nullifying a vessel from its normal usage) that come up on Shabbos;
how to work with opening up various different types of boxes;
Is There a Problem with Spreading Foods (e.g., Peanut Butter, Cheese, Hummus, etc.) onto Challah, Matzah, etc. on Shabbos?;