I am the Lord your God, Who has taken you out of the land of Egypt, from the house of slavery

Upper left-hand quadrant:
After R. Judah ben Bava was slain, they brought out R. Judah ben Dama for execution. The day was the eve of Shavuot.
The Ten Martyrs

Upper right-hand quadrant:
"The sound of the shofar grew stronger and stronger (lit: proceeds and becomes very strong)". This shofar is the left horn of Isaac's ram; the right horn is designated for the time of the messiah.
S.Y. Agnon, Atem Re'item, p. 136.

Lower left-hand quadrant:
Aaron held out his arm over the waters of Egypt, and the frogs came up and covered the land of Egypt.
Exod. 8:2

Lower right-hand quadrant:
R. Levi said: The Holy One appeared to them as though He were a statue with faces on every side, so that though a thousand men might be looking at the statue, they would be led to believe that it was looking at each one of them.
Pesiqta de-Rav Kahana