ob1 -

i don't doubt that the wheel was a symbol, possibly to bring good luck or spirits to the building, builders, or occupants.

what i don't see is that they were useful computers AND something that was divined by nature, god, spirit, or devil.

there are plenty examples of folk symbology running the gamut of luck charm, spirit ward, family seal, etc., etc... (think hex signs on barns, etc.)

so, while i am open to this idea - i don't think these things do both... they may be a geometric cliche, they may even be a derivation of a useful building or layout technique that were used for doing very specific tasks that somehow migrated to 'symbol' and pattern as a catch all, they may be graffiti... but i am suspicious that they are enshrined with too much hidden meaning AND a practical tool at the same time.

perhaps i'm wrong... folk history is a murky thing, as those that control the present can change the past...