Bit pattern
scratched into metal plates by an engraving tip mounted
in an X-Y flatbed plotter?
How about laser-etching? Possibly onto small aluminium
discs, maybe
about 5" in diameter. Of course, if aluminium proved to be too
heavy, you could probably do it with a thin aluminium coating
deposited onto a clear plastic disc.
And then cover it with another layer of plastic, for physical
protection.
Hmm, I bet you could fudge something with chemicals instead of the
aluminum layer, so you can "etch" it after the plastic layers are all
put together....
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