Game Tiles Castle Wall Pack is made of "Dwarvenite" and expands the Games Tiles Base Set. This pack was initially available as an Add-On pack to the Game Tiles Kickstarter. The pack comes in both painted and unpainted versions.
The Game Tiles Castle Wall Pack comes complete with these 16 pieces:
(10) Wall, Straight, with Window
(6) Wall, Straight, with Arrow Slit