I improvised this design in class using an envelope that was lying around.
I liked being able to use the flap of the envelope as part of the nun's gown - so I was using the envelope "fully" and not simply as a rectangular sheet of paper!
Thinking back, I was probably inspired by Vietnamese origami master Giang Dinh's evocative abstract human figures:
You must check out his achingly beautiful origami faces, animals and figures. I saw his gorgeous work in a book of photographs from an origami exhibition, titled Masters of Origami: At Hanger-7.