The Pottermore Insider Blog has been updated with second of two posts featuring how the Hogwarts Crests were created.
The first post looked at Gryffindor and Ravenclaw, while this one focuses on Hufflepuff and Slytheirn.
"The Hufflepuff crest proved to be the most difficult creation for the team. There is a limited amount of detail about Hufflepuff house in Harry Potter and The Philosopher’s Stone and they were aware that they needed to work a little harder to make the crest feel authentic and representative of the Hufflepuff nature. There was also the question of how to show the badger as a tenacious animal, to show Hufflepuffs as unafraid of hard work."
"The art team tried out a number of different snakes for the Slytherin crest, as they wanted to ensure the one they used didn’t resemble a particular type of serpent (such as a boa or a cobra). The coil of the tail was another focal point as the artists wanted the snake to look natural, but not inactive."