When an ingredient, the Fuel, the needed extension or tool, or enough energy is missing, or the mastery is below the recipe's requirement. A normal recipe cannot be worked at all below its required mastery; the recipe card shows the level it needs next to the mastery icon. Star crafts and autopsy work are the exception: they can be attempted below the requirement, with a chance per tick instead of a guaranteed step.

Extra recipes. The higher furnace, anvil, woodworking, kitchen and factory tiers make everything the tier below them does; each station page lists what its next tier adds. Kitchen Oven II and Embalming Table II add no recipe: each of their ticks takes half as long.

Pieces built next to a station that unlock some of its recipes: a Tool Rack or Fine Tool Rack beside the woodworking and stonemason benches, a Hardening Bucket beside the anvils, Bellows or a Casting Table beside the furnaces, and the attachments of the factory benches.