Constructing a Quine from Kleene's Second Recursion Theorem

The author describes their experience formalizing Kleene's Second Recursion Theorem, a proof that the existence of Quines (self-referential programs) is a consequence of the theorem. They used the untyped lambda calculus to formalize the proof and found a clean and concise presentation of the theorem. The author discusses the benefits of formalization, such as clarifying definitions and proofs, and notes that it can be a source of insight and creativity.