Dark Stucco Windows can be crafted in your Crafting Menu (opened by typing "Q" as the default key), after the according crafting-recipe has been unlocked by taking/crafting Dark Stucco Walls for the first time (which in turn was unlocked by taking/mining Stucco Walls). To craft 4 Dark Stucco Windows at once, you'll need (as of R26 in December 2015): Currently windows cannot be found in the game-worlds of Creativerse as items (cannot be discovered in Treasure Chests nor obtained from any Creatures). However, a few crafting-recipes for special kinds of windows can be found as rare Recipes.