[g.l.amour]

@puzzdre

now this is where i might have some phantoms in my head. but

wouldn't it be better to leave the purple circles W too. i always want to help the water flow to those regions, because if you don't help the water it will automatically flow straight to outlet; leaving the north and south pins (looking from center pin) relatively uncooled. this is where my guessing starts. it could very well also be that the few canals force the water to the north and south anyway. so that your N N solutions might be as good, if not, better.