Adding a pseudo-random numbers generator to the sed-script itself.

[Circiter]

Instead of relying on the sedtris.sh to generate randomness during gameplay,
I propose the inclusion of a simple [rule 30 based] PRNG into sedtris.sed. It costs
no more than approximately 20 lines of code.

(Though you still need to feed some entropy at startup, either from date-time or from /dev/urandom, or manually...)