DEFINITION: a slipper or light shoe without a back.
Until recently, I was not completely sure of the defining characteristic of a mule. Not the animal, although that too was a very enlightening moment (offspring of strictly, a male donkey and a female horse) but the shoe that has been seen on many a fashionista foot lately. So basically, it can be flat or high, open or closed as long as there is no back. Are you a fan??
photo credit: whowhatwear, Pinterest