A different operation, not a re-spelling. Per-block repeat hands every
block its OWN doubled output, which is a distribution the NEXT block has
never seen, so a ten-block span creates ten seams. A span loop leaves
every block receiving input from its normal predecessor and creates
exactly ONE, at the wrap from last back to first.
That is the obvious candidate explanation for the sweep's central
puzzle: 31,40 and 35,40 survive two extra passes while 31-40 collapses
at the same count. Same total extra block evaluations, so the same cost
— only the seam count differs.
The span's first block does the work (walking
model.model.diffusion_model.blocks, which the hook cannot reach since
original_block closes over one block only) and the rest of the span
becomes a pass-through, because the model's own loop still calls them.
Refuses a non-contiguous selection with a note rather than silently
looping min..max, which would run the blocks deliberately left out.
Under video-only, text and audio rows get the span ONCE — not zero
times, which would skip those blocks entirely for audio and is a
different, worse intervention than "do not repeat them".