You need to carry a heavy sack of flour to a neighbor on Yom Tov. Can you use a pole?
H1-2: Carrying is permitted but heavy loads need shinui. If you normally use a pole: carry on your back. If normally on your back: carry on your shoulder. The change must be visible.
Question 2
Can you send a gift of raw grain to a friend on Yom Tov?
H7: Gifts must be things the recipient can enjoy TODAY. Grain requires grinding (forbidden on Yom Tov), so it's useless as a holiday gift. Send flour, not grain. Wine, not grapes that need pressing.
Question 3
You borrow a candle flame from a neighbor. Whose techum does the flame follow?
H16: A coal (physical) follows its owner's techum. A flame (non-material) has no techum restrictions at all. The Rambam distinguishes between the material and the immaterial — a flame isn't an "object."
Question 4
You invite guests. They want to take leftover food to a place you can't walk to. Is this permitted?
H12: Food served at a feast follows the host's holiday limits. Guests cannot take it beyond where the host is permitted to go. The food's legal "home" is the host, not the recipient.
Question 5
Why can't you send a Yom Tov gift with a delegation of multiple people?
H8: A group of messengers looks like a commercial operation — a weekday delivery service. One person carrying a gift: personal, festive. A delegation: business. The holiday must feel different.