A large slab of slate stands on point on a stainless steel base. The work is a continuation of themes first expressed in Key to the Sea, but on a larger scale. Portal has, "a sense of largeness that doesn't come any other way. The interior of this slot is polished, by the way, which is fun to touch," said Curtis. "Slate has a very nice hand about it, but it does make you want to look through it, feel through it, put your hand through it. There's a gravitas to reaching through a stone."