The doorway opened and the pair of them made their way into the giant chamber. Three women seemed to be working on some sort of magical textile, the threads and strands weaving into and out of each other as it covered the walls of the room just like an Arithmancy problem, except that this was infinitely complex. There was unseen music coming from the room and Percy's eyes darted around in an attempt to figure out where it was coming from, only to realize that the luminescent strands weaving around like Arithmancy was humming both with power and with the sound of the orchestral music.