Upper left-hand quadrant: After R. Akiva was slain, they brought out R. Hanina ben Teradion for execution. The Ten Martyrs
Upper right-hand quadrant: … Sinai plucked itself as a priest's portion is plucked out of the dough. For the Holy One said: Since their father Isaac was bound upon this mount, it is fitting that his children receive the Torah upon it. Mteh 68:9.
Lower left-hand quadrant: Every time R. Hiyya bar Ashi fell down upon his face, he used to say, "May He who is everywhere save me from the impulse to evil." B. Kid. 81
Lower right-hand quadrant: Locusts invaded all the land of Egypt and settled within all the territory of Egypt in a thick mass; never before had there been so many, nor will there ever be so many again. Exod. 10:14-15