(Mishnah): If a Shofar was split and he glued it it is invalid. If a person glued together pieces of Shofar, it is invalid.

If it was perforated and the hole was plugged, if the hole had prevented the Shofar from being used, it is invalid; otherwise, it is valid.

(Gemara): The Mishnah taught the law of a split Shofar that was glued, according to the view of R. Noson. R. Noson said that if a Shofar had a hole and it was filled with Shofar material, it is valid. (According to the Rabbanan who disagree with R. Noson , the case of our Mishnah would certainly be invalid.)

R. Chiya quoting R. Yochanan: We can also establish it like R. Noson, as the Beraisa teaches - If a hole was filled with the same or with a different material, if the filling prevents effectively blowing the Shofar, it is invalid; otherwise, it is valid.

R. Noson: If it was filled with the same material, it is valid; with another material, it is invalid.

R. Chiya quoting R. Yochanan: The Mishnah teaches that if the presence of the hole had prevented the Shofar from being effectively sounded, it shows that the filling assists the sound and it is invalid; otherwise, it is valid.

R. Aba bar Zemina quoting R. Zeirah: It is only invalid if he filled it, but if he did not (and it can produce a sound) it is valid, as all sounds are valid in a Shofar.

R. Yaakov bar Acha: Abba bar Ba asked Rav - (When the horn is still attached to the animal, a bone protrudes into the airspace of horn. This bone is normally removed.) What if he (instead) bored a hole (through the middle of this bone)?

Answer (Rav to Aba): In Ein Tav they use such a Shofar (i.e. it is valid).

(Mishnah): If a person blows the Shofar into a pit, a cistern or large earthenware vessel - if he heard the sound of the Shofar, he fulfills his obligation; if he heard the echo, he does not fulfill his obligation.

Similarly, one who is passing behind a Synagogue or his house is close to a Synagogue and he heard the sound of the Shofar or the Megilah, if he has intent, he fulfills his obligation; if not, he does not fulfill his obligation.

Even though this person heard and that person heard, one had intent and one did not.

(Gemara - R. Yosi ben Chanina): The Mishnah said 'and similarly one who is passing [behind a synagogue]' - but if he actually stood there, one can assume that he had intent.

If a person inserted a Shofar into another Shofar and blew, if he heard the sound of the inner Shofar he fulfilled his obligation; if it was the sound of the outer Shofar, he did not.

Question (R. Avina): If a person (softened up and) turned a Shofar inside out (like a garment) and blew, is it valid?

Proof (Beraisa): If a person filed down a Shofar, whether inside or outside, it is valid.

Deduction: The Beraisa only discussed filing down, but if he would have turned it inside out, it is invalid.

Question: What is the difference?

Answer: If it is turned inside out, its hollow is annulled; if it is filed down, its hollow still remains.