I keep forgetting that not everyone has PBP...

Unfortunately not having PBC I'm relying on the manual only...

RandomSeed is W0
I don't know if B0 or B1 is the Lowbyte... let's say it's B0
LightSelector is B2

so the code would go something like...

Read 0,B0
W0=W0+23
Write 0,B0

Loop:
RANDOM W0
B2=W0 & $000F
Gosub BlinkyLight
Goto Loop

Does this make things any clearer?