The *Laws of Form* (Spencer-Brown 1969) wikipedia 
, page did not enter the world of mathematical texts without presupposition. The problems to which the text responds, as well as some of the solutions presented, become accessible to a different and possibly deeper understanding when the *Laws of Form* are considered in the context of the history of mathematics and logic.
Convergent evolution can give creatures analogous structures even though they cannot mate. But, in the intellectual world analogous structures take advantage of interfertilization and find new applications.
The occurrence of identical subpatterns within a Form. ⇒ Dnet Dialect