Asciihero can shuffle all segments to appear in a random order if you set the
:asciihero-shuffle-style: document attribute to random.
If you want the segments to be random, i.e. shuffled but always the same each time you render the document you must set the :asciihero-shuffle-seed: attribute to anything.
Asciihero will then use that seed every time it generates a random number for shuffling.