Stonehenge, and a multitude of other standing stones and pyramids and slots and Mayan calendars are examples of computers specialized for time, e.g. seasonal and astronomical calculations.

I could chip an abacus out of flint in a few days, if you'd spot me wood for the shafts. Longer if I had to chip the shafts out of flint too.

It's possible, though the work of several lifetimes, to chip a Babbage Engine out of flint. Though I think obsidian would probably be better, in terms of taking a polish necessary for precision machining.

Other processor architectures could be implemented in macro-scale silicon. A classic Turing machine "tape" could be implemented as pits on a long stone slab that actuate smooth pebbles constrained in a frame over the "tape".

Sand in an hourglass, come to think of it, represents macro-scale silicon processing.

This is why I never argue political economics with you, Tom. You just can't think outside the corporate libertarian box.