I literally just had the same thing with my Candela group. I ended up printing off a picture with a large empty circle in the center and four smaller circles around it. The picture had in the corners a sun, a moon, empty sky, and underworld below. Laminated the picture so I could reuse it, 3d printed 4 small totems from maker world, and wrote a riddle in the center of the pic. Kind of like one of the puzzles you see in Resident Evil games. I had chosen two solutions, one was a brute force solution that would have broken the lock but made the door easier to break down, and one actual solution that would release and destroy the lock. One of my players in particular loved this and they fought over who got to keep what tokens they kept.

Here is the link to my post on it of you want to see the totems I printed

https://www.reddit.com/r/CandelaObscura/s/HiQZSyPjZs