What is the status of food cooked on Shabbat or a light kindled forbiddenly? The Gemara in Chullin (ט״ו ע״א (15a)) brings a Tannaitic dispute, and the poskim built a clear ladder from it.
R. Meir: unintentional - may be eaten even on Shabbat; intentional - forbidden on Shabbat, permitted after. R. Yehuda: unintentional - permitted only after Shabbat; intentional - forbidden forever to the cook himself. Shulchan Aruch (OC 318:1) rules like R. Yehuda.
Work a non-Jew did for a Jew is forbidden to that Jew on Shabbat, and after Shabbat one waits "bichdei she-ya'asu" - the time it would take to do it (SA OC 325:6).
Question: if the non-Jew did it for himself, why forbid it? Answer: indeed, if he did it for himself a Jew may benefit (with conditions).
Build a 2×2 table: unintentional/intentional × on/after Shabbat, per R. Yehuda.
Halakha also structures what happens after a mistake - educating, not merely punishing.
Test yourself before marking the lesson complete.
Whom does the Shulchan Aruch follow on ma'aseh Shabbat?
