Responsa for Bava Batra 120:4

אבל אם רצה כונס לתוך שלו ומוציא: איבעיא להו כנס ולא הוציא מהו שיחזור ויוציא ר' יוחנן אמר כנס מוציא וריש לקיש אמר כנס אינו מוציא

— R. Johanan said that though he has drawn back [the wall] he may still make projecting beams, while Resh Lakish said that once he has drawn back he cannot later make projecting beams. R. Jacob said to R. Jeremiah b. Tahlifa: I will explain this to you. On the question of projecting beams there is no difference of opinion [between the authorities], and both hold that they are permitted. Where they differ is on the question whether he may restore the walls to their former position, and the above statement should be reversed, [i.e.,] R. Johanan said that he may not go back to the original position and Resh Lakish said that he may. R. Johanan ruled that he may not, In accordance with the dictum of Rab Judah,<span class="x" onmousemove="('comment',' Whom the law follows in this matter, so that, as usually in a dispute between R. Johanan and Resh Lakish, the law follows the former. ');">³</span>

Shut min haShamayim

Teshuvot Maharam