Comment by Shrezzing

There's quite a lot of other constraints too. Lots of goods aren't allowed to sit side-by-side, for example, anything explosive goods cannot sit within n containers of hazardous chemicals. Because goods codification is so low-fidelity, lots of things which aren't actually explosive/hazardous can't be stored in close proximity, because we can't differentiate them from things which are actually hazardous/explosive.