Additional physical understanding may or may not be included flexibly as additional production rules, this way further tailoring the generated chemical search space. In this respect, the use of a grammar in computational screening also blurs the boundary between mere discovery and purposeful design. While (exhaustive) searching in any enumerated space is a discovery process, production rules in grammars offer the prospect to introduce partial understanding of design rules (in the present example the understanding that balanced oxidation states favor stability). This partial understanding is likely not sufficient for a targeted atomby-atom design. However, formulated as production rules within a grammar is allows to focus the search space to those materials that are consistent with the present understanding and unbiased regarding the rest.