Configurations of planar non-overlapping closed curves
Composition of closed, non-intersecting planar curves, called *boundaries*, constructs a formal diagrammatic language, independent of an interpretation as logic. The alphabet is a singleton set of symbols consisting of the *empty boundary*, { ○ }, which is called a *mark*.
A word consists of replicates of marks composed in a nonconventional manner. Since boundaries have both an inside and an outside, replicate symbols can be juxtaposed in two ways: on the inside of the original boundary and on the outside of the original boundary.
Rather than one "concatenation" operator, there are two: SHARING is composition on the outside, while BOUNDING is composition on the inside. The formal language consists of the set of composable boundary forms.
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