From reading other comments, it sounds like the programming equivalent to coding a product without any tests, validation, exception handling. Risky and very likely to lead to a unrecoverable spaghetti mess, but we've all been in that state where the ideas are just free flowing unimpeded by caution.

Considering that Honnold completed the free solo in around 4 hours, I would suppose it is an experience of a similar nature, albeit with greater personal risk involved.