Jean-Paul Delahaye is a professor emeritus at Université de Lille 1 in northern France, a researcher at the Research Centre in Computer Science, Signal and Automatics of Lille (CRIStAL – CNRS / Centrale Lille Institut / Université de Lille), and the author of numerous popular science books on mathematics. Personal webpage: https://www.cristal.univ-lille.fr/~jdelahay/ [3]