If one takes a pair of scissors as security, he transgresses for each blade separately (if he does not return that at the correct time, since they are needed for the sustenance of the borrower). But if he only took one blade as security, he only transgresses for that one.

One who takes a pair of cows as security transgresses for each one separately. If he took only one of them, he only transgresses for that one.

(Mishnah): If a house and its attic belonged to two different people and the house fell, they divide equally the wood, the stones and the dirt.

And if from the way in which it fell, we can identify whose stones would have been broken, we can divide the stones up accordingly.

If one of them recognises some of his stones, he takes them, and they go towards his portion in the division.

(Gemara) - Beraisa: If the house collapsed like an oven i.e. from the bottom, then the top stones would have broken. If it fell down sideways, then the bottom stones would have broken.

If one of them recognises some of his stones, he takes them (even if the other one does not agree to it) and they contribute towards his portion of the division.

R. Hoshiyah: This ruling (that if one recognises some of his stones, he can take them even if the other one does not agree to it), implies that as long as he is sure, he may take it, even without the other's consent.

Mishnah in Maseches Demai: 100 portions of tevel (untithed produce - in this case, although Terumah Gedolah was taken, Maaseros and Terumos Maaser were not) that became mixed with 100 portions of chulin (tithed produce), he should take out 101 of it and sell it to a Kohen (as it contains Terumas Maaser). If there was 100 tevel and 100 Maaser, he should take out 101 (making all of it terumas maser. He then gives it the Levi who sells it to the Kohen for a reduced price).

R. Yosi: If you say take 100, I would say that all that he took was chulin, so he has not done anything because he cannot separate chulin to fix up tevel. Rather, he should take 101 in order to separate terumah and terumas maaser from the tevel.

Question: Which of them (house or attic owner) must build the foundations?

Answer (R. Zeira): The one who lives on the ground floor; otherwise the other one will say, "You are supposed to hold me up, so you must build the foundations''.

R. Ila: The one who lives in the attic, (as the house owner will say, "I do not need them!''), as builders say that they both need the foundations.

. This Beraisa is a support for this statement of the builders...

If his fallen house was near the wall of his friend's courtyard (and his friend's courtyard is higher than his fallen house), his friend should not say to him, "You begin to build the wall and I will begin to share the cost only from the height of my courtyard upwards''. Rather, he must share the costs from the foundations upwards.

If his courtyard was near cavities and caves (and the courtyard was more elevated than them), he does not need to build a wall between them and his courtyard (to prevent hezek re'iyah - the damage of others from seeing him in his own domain).

Rejection (R. Yosi bei R. Bun): The Beraisa is referring to courtyards like those of Bishan, that the upper one cannot build until the ground level is first built.

If a house and its attic belonged to two, if the attic floor collapsed and the house owner does not wish to fix it, the attic owner can go down and live downstairs until the house owner fixes the upper floor.

R. Yosi: The house owner must give the ceiling and the attic and the attic owner must give the mud (that is put between the boards).

(Gemara) - Beraisa: If the floor (of the attic) broke where the oven is, he can go down below (to the house). If it broke where the stove is, he can (also) go down below. However, the house owner can say to him, "Make yourself a ladder (to use to come down when you need to use the oven/ stove), so that you do not walk through my house when you are not using the oven/stove.''