Fresh grain has grown and is blocking a functional window. Does it validly reduce the window below the threshold?
Halacha 1: Growing grain does not reduce a window because the owner plans to cut it down before it damages the wall. The key is that reducers must be things the owner has no intention of removing.
Question 2
Can an eight-month premature infant placed in a window on Shabbat reduce the opening?
Halacha 2: An eight-month premature infant on the Sabbath is among the valid reducers — it is forbidden to move on Shabbat (muktzeh), and since it cannot receive impurity, it is pure and reduces the window.
Question 3
Less than an olive-sized piece of corpse flesh is placed in a window to reduce it, while a full olive of corpse flesh is inside the house. Does the reduction work?
Halacha 5: Flesh from a corpse cannot reduce a window against the impurity of corpse flesh inside — the same category combines. However, a sub-threshold bone CAN reduce a window against flesh (they are different types).
Question 4
Earth from a beit hapras was baked into a brick and placed in a window. Does it reduce the window?
Halacha 5: A brick made from beit hapras earth is pure. The Sages only decreed impurity on a clod of earth in its natural state (gush kivriato) — a brick is a new form.
Question 5
An earthenware vessel is placed in a window with its opening facing outward. Under what condition does it validly reduce the window?
Halacha 4: An earthenware vessel placed with its outer surface facing the impurity (and thus not contracting impurity from its outer surface) can reduce a window — but only if it is so disgusting and perforated that the owner would not think of moving it.