PINE Design is a architecture company in Cielis owned by Mallory Pine. it's first appearance was in book 8, when Emily had just gotten back from confronting The Elf King. It is also the place Emily saw Trellis there, for the first time in book 8.
Mallory pine was designing a new school for Cielis, because the old school was designed like Yarboro Prison. Mallory thought the council 'didn't know the effect it would have on the kids.