Suddenly I wonder, can one define an infinite series of Omelas-type societies along these lines: Omelas represents the case n = 1 where n is the number of children who must be kept in permanent suffering in order to maintain social stability. We could perhaps rename the n = 1 case the "Monomelas" scenario. Then n = 2 is the "Bimelas" case, n = 3 is the "Trimelas" case, and so on.
There's a hypothetical "Nomelas" where n = 0, but its existence is doubted. There's even the possibility of n < 0, which would suggest that one or more children must be kept in permanent bliss in order to sustain society, but let's not get carried away here.
~Chara
