chasing innovation based on assembling known components, as might be true of cooking recipes or software systems, we can define an average usefulness [@Fink-RPF-2016arxiv] on which to base an intelligent symbol-acquisition strategy.

However, when interrogating unknown systems, we may need to just rely for innovation on whatever new thing we have managed to discover. This will be without knowing in advance of use how frequently it will turn out to be useful – because we do not have access to the world-dictionary of our unknown system. This “explorative” view of innovation is distinct from that of the more “assembly”-focused view of innovation (combining known things) described above. Therefore we also show results for discovering the symbols in a random-order, where indeed we [can]{} see the sudden bursts of discovery we might normally expect from terms like “innovation” and “serendipity”.

Unlike the treatment in Sood et al [@Sood-MSGP-2010prl], these world dictionaries are static, and do not involve components (symbols) which appear as new, and then later may die off and disappear, taking the words they appear in with them. However, one might – although I do not do so here – consider interrogations where symbols are not only learnt but forgotten, 