On Mon, Jul 19, 2021 at 3:58 PM Luke Kenneth Casson Leighton <lkcl at lkcl.net> wrote: > nope - screwed up. working out why, now. nope - moving on. means that the DCT algorithm, annoyingly, will have to be done Vertical-First due to the inner loop swap-in-place. i can live with that for now. l.