Simple stone texture without adornment for floors (or walls, if we want to get creative).
A compliment to these requests:
https://feedback.inkarnate.com/champions/p/ironstone-brick-texture-without-design (this one has a subway tile design with stones)
https://feedback.inkarnate.com/art-requests/p/subway-tile-red-brick-texture (red bricks in subway tile pattern)
