I think we would have been better off explaining our basic math system and perhaps then a basic language system. Show what the symbols we use mean and then use them--so that they can learn what we do (and how we do it). After explaining basic math, explain basic chemistry by symbolism and perhaps a periodic table of elements. Make and show patterns to help. In my attachment, I showed the numbers using internal angles as well as dots to count. Then toss in a demo about making larger numbers by showing increasing numbers and ways to manipulate numbers (P.E.M.D.A.S.). We could even give them a time-scale by representing the speed of light in seconds, minutes, hours, & days. If they have anything like modern math, then the entire thing should be easy to understand. Finally, a sample of matter (ie: Carbon-14) could work as a rough clock by showing decay & using that as a clock.
Mounting 7 of these plates each probe should hopefully also decrease the chance that part of all of it is illegible.
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