Four enormous wooden carvings are in the entrance to Ilvermorny School of Witchcraft and Wizardry, one for each of the school’s houses. These are used to sort the students. The enchanted carvings react when the new students stand on the Gordian knot in the entrance hall to signal if they want the student to join their house. The Horned Serpent has a jewel in its forehead that will light up. The Wampus carving will roar. The Thunderbird will flap it’s wings, and the Pukwudgie will raise it’s arrow into the air. If more than one carving wants a student, then the student gets to decide which house they prefer to join.
About once a decade a student is offered the choice of all four houses. Seraphina Picquery was the only witch of her generation to receive this offer, she chose Horned Serpent (Pm).