During my 2 hour vaccuming of nearly my entire house, I thought of this thread and wondered:

How might three or four Roomba's play well together?

I'm not in a big house at all, but a dusty/hairy/dirty one. Maybe each Roomba could have its own "turf", likely dictated by the location of its charger (far from the others). But if they saw each other, they'd have to learn it's not a wall they are seeing, but one of their own.

Um, on second thought, that would tripple or quadruple their (1) human hunting (2) rampage of death.