Lettering, numbers, pictures that are part of a cookie or cake itself. (It's all one dough).
understanding the distinction between building with קרקע (structure) and building with כלים (utensils);
more examples of "מבטל כלי מהיכנו" (nullifying a vessel from its normal usage) that come up on Shabbos;
introduction to squeezing towels, paper towels, napkins, etc.