>>6genii?
I think `geniuses' is more correct. Normally I'm all in favor of sticking to the correct mother-language pluralization of nouns, but if you want to do that for `genius', surely there is some sort of obligation to stick to the mother-language meaning of the word, is there not? And my OLD gives:
genius ~ii,
m. [GIGNO; cf. OHG
chunni, AS.
cynn]
1 The male spirit of a
gens existing during his lifetime in the head of the family, and subsequently in the divine or spiritual part of each individual.
b the personification of one's natural appetities.
c (applied by a parasite to his patron).
d (ancient definitions, etc.).
... 2 (attributed to gods).
b the
genius of an emperor, regarded as an object of worship.
... 3 (attributed to places, corporations, and other things); (in writings) talent, inspiration
...(Where I've not included the citations because they're a pain in the neck to type and nobody really cares anyway.) So if we were to stick directly to that definition, only
3 would really come close to our modern usage of the word, and it would be more of a noun anyway, so that we could talk about Carmack's genius, or possibly of his genii, but to call him a genius wouldn't make any sense.
On a side note, we could then discuss the
genius loci* of a particular setting, or perhaps community, or perhaps even of a particular machine, in which case ``conjur[ing] the spirits of the computer with our spells'' could be seen to not only invoke desired behavior through a program, but to invoke a state of inspiration or enlightenment through programming.
* While I'm waxing eloquent, http://www.eldritchdark.com/writings/short-stories/78/