Mein Hut, der hat drei Ecken,
Drei Ecken hat mein Hut,
Und hätt er nicht drei Ecken,
So wär es nicht mein Hut.

With a scarf:
(Place scarf on head like a hat)
My hat, it has four corners,
Four corners has my hat,
And had it not four corners,
It would not be my hat!

Add additional verses with scarf behind your back like a cape, on your lap like a blanket, next to head like a pillow, etc