Location for the clue that begins, “I’ve met some Strange…”

In Avenger’s Campus is Dr. Strange’s ancient sanctum. To the right of the entrance to the ancient sanctum is a large, multi-sided box that looks like a sculpture. Just beyond that is a black-and-white checkered floor that has been tiled to look like a vortex hole when viewed from a specific location (optical illusion). In that tiled area, there are four books hanging in different areas around the edges of the space.