The Birds' Head Haggadah
This Passover, I learned about the Birds' Head Haggadah, a 13th century Ashkenazi illuminated manuscript from south Germany. The guy next to me at shul told me that the reason for this was because of the strict interpretation by the Ashkenaz communities of that time of the Biblical commandment against making graven images. By altering the human form, the illustrator was deemed to have circumvented the prohibition.
I have a weakness for calligraphy and illumination and I admit to finding these manuscripts exquisitely beautiful. However, it seems to me that by making the human figures have the heads of birds, the makers of this haggadah inadvertently made them look like the very gods of their persecutors in Egypt.