To be fair, this is a test case that OpenAI claims to my knowledge was their core test case for GPT4. If this was an outstanding industry test case of note, references would be helpful. OpenAI has also not disclosed how they were able to finally accomplish this, so it’s possible solution was more of a hack than actually training the model.
maybe modify it slightly? a poem starting with each consonant in alphabetical order? a poem where every word starts with a particular comon letter like "t"? the same but in reverse alphabetical order
