Upper left-hand quadrant: When the children of Israel were standing at the bottom of Mount Sinai they attempted to mislead God (lit. they attempted to steal God's opinion) as it is written. "All that God has said na'aseh ve'nishma (we will do and obey)." Exod. 24:7.
Upper right-hand quadrant: R. Simeon ben Gamaliel and R. Ishmael the High Priest were seized to be executed. R. Simeon burst into tears. R. Ishmael said to him, "Avrekh, you are but two steps away from being put in the bosom of the righteous, yet you weep!" R. Simeon: "My heart fails me, because I do not know why I am to be killed." The Ten Martyrs
Lower left-hand quadrant: Why did He command the women first? - Because they are prompt in the fulfillment of the commandments. Another explanation is: So that they should introduce their children to the study of the Torah. Exod. Raba 28.
Lower right-hand quadrant: For if you do not let My people go, I will let loose swarms of insects against you and your courtiers and your people and your houses; the houses of the Egyptians, and the very ground they stand on, shall be filled with swarms of insects. Exod. 8:17.