GraphJam recently provided this Venn diagram of the three character sets:
As the comments on GraphJam point out, this is a somewhat simplified view. For instance, just because the letters look the same, doesn't mean that they represent the same sounds. Take, for instance the Cyrillic letter "B"; it's Latin equivalent is "V".
So, it may not be perfect but if it's your kind of thing, then go ahead and purchase it on a poster, tie or iPhone case!
If you have a few more minutes, take a look at the following articles:
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