Having proven your worth in NASA's test, you are allowed to work on the alien message. NASA experts tell you that they suspect that the language is a transcription of our letters/words written left to right. They need your help to figure out this writing system and how to get from English letters/words to this language. Use the provided Rosetta Stone for that. Return to them the rules of this writing system so that humans can interpret future alien messages. Do this and they'll even let you write the first message back to them! Be aware, this is not easy; it's already driven half of NASA's linguistic and cryptography experts crazy. Good luck!
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Accepted answer will be the first answer that provides all rules for this writing system that you can determine from the Rosetta Stone and can prove it by transcribing a short message of your choosing to the aliens. I recommend cooperation: if you see a pattern but can't get the rest, contribute what you have, maybe it will be useful to the others. There are several rules to find.