-Rules can apply not only to L<LaTeX::TikZ::Set> consumer objects, but also to the L<LaTeX::TikZ::Mod> consumer objects they contain.
-The are stored as L<LaTeX::TikZ::Functor::Rule> objects.
+Rules are stored as L<LaTeX::TikZ::Functor::Rule> objects.
+They can apply not only to L<LaTeX::TikZ::Set> consumer objects, but also to the L<LaTeX::TikZ::Mod> consumer objects they contain.
+When the functor is called against a set object and that the returned set is different from the original (as told by C<==>, which defaults to object identity), then the functor is also applied to all the mods of the set, and their transformed counterparts are added to the new set.