[imode]

Definitely. Or mechanical logic gates. But the surface area would very quickly become an issue for such a project, and you'd need to assume only a certain few tools.

[carapace]

True. I wonder what kind of computations people would need to do that would make it worthwhile to make big, slow computers?

I bet it would be easier to make up "sacred dances" that incorporated processing in the motions of the dancers.

And let's not forget that a human with an abacus can do a great deal of the math required for everyday life. :-)