Thanks! Its cos I found having streams rejoin them selves to reuse the [s>] so tricky.
I figured if the stream never really split i wouldn't such have a headache with merging.
I found the interactions with the source block very interesting
when I first tried [n>][<>] it was[consu][n>][<>]
and gave a completely different output
--->2s vs --->....s,s,s,s,s,s,p