Hello Math-Fun, (a few friends in copy) this is in French — but easy to understand with the illustrations. In short: 1. seq D 2. digits of D form seq S 3. seq S is turned (on a 2D square grid) into a single-digits spiral 4. This spiral is fractal: its odd digits reshape the spiral itself (the digits have a peculiar design) ... This idea came to me after a discussion on SeqFan about the precise (and seemingly impossible) definition of the term « fractal ». This was submitted this morning to the French magazine Tangente: https://cinquantesignes.blogspot.com/2020/08/partir-en-recursion.html?m=1 Best, É. Catapulté de mon aPhone