Spiral Stairs going Down for RPGs
Open Forge, Dwarven Forge, Dungeonstone, and Hirst Arts compatible 2" x 2" downward spiral stair pieces. They are textured mostly like the gothic floor/wall pieces from Hirst Arts than anything, though the texture is custom-made by me. The height is compatible with Dwarven Forge pieces, and is approximately 11/32" high on the "regular floor" portion.
This thing includes both types of stairs, so you can print whichever (or both) as needed for your dungeons.
It's the perfect compliment to Open Forge (and the others) to make it clear to your players that a set of stairs actually goes down rather than up.
Enjoy!