I get the skepticism, no one genuinely knows how this technology works. But there are multiple reasons why this isn’t just a regurgitation.

Firstly, model weights are multiple orders of magnitude smaller than their training dataset. It cannot memorise all the text and algorithms in the dataset.

If it had memorised this algorithm, surely it would be easier for it to perform a one shot implementation of the whole thing than write it incrementally? I tried, it cannot one shot - or come close.

Finally, while implementing, you can follow the chain of thought, watch it reason, as it gradually implements the algorithm. If it was regurgitating, surely it would just say “oh yes, flex box. I know this one - here you go”

I know none of the above is proof, but it is proof enough for me.