It's created when molten iron is poured into a mold and allowed to cool (a.k.a. cast) to form a shape — in this case, a pan, ...

The researchers used their optimized direct laser writing approach to create high-resolution 3D woodpiles using multiphoton DLW. (a) A schematic of a 3D woodpile (b) A 45°-oblique-view SEM image ...