Also relevant: cards themselves could have a type: are they posing a question? are they a summary of something else?

Being of a particular type and having a link that places it in a relationship of a particular type are often two sides of the same coin.

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Using lowercase for properties and uppercase for classes: if you are someone's `father` you are a `Father`. If something has you as a `colour` you are a `Colour`.

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I need to look up how Dick Hudson's *Word Grammar* work deals with this "redundancy" as I seem to recall he does.