We expect something ornate
Ornamentation with meaning (Allah is the light)
Tawhid: the defining doctrine of Islam. It declares absolute monotheism—the unity and uniqueness of God as creator and sustainer of the universe.
Illustrations from the Qur'an: Sura 110: The Divine Support - The Wave of Kanagawa
Illustrations from the Qur'an: Sura 57: The Iron - Horse
Prayer in the form of a lion: "Ali bin abi Talib, the victorious lion of God, may God be pleased with him"
A Kufi Square - hard geometric lines of text, also used in architecture
But it's not all religious:
"This morning I shot an elephant in my pajamas.
How he got in my pajamas, I'll never know." Groucho Marx