 Even though in structure it was ostensibly orientated on Euclid’s Elements, Porta’s Elementorum curvilineorum libri tres (1601/1610) flopped, probably because Porta had coined so many fantastic new words for (allegedly) new geometrical shapes, which was perhaps and with hindsight one of his most original ideas (Saiber 2017). In fact, Porta’s knowledge of classical and contemporary mathematics seems to have been vast, but superficial. Using a language that is both colloquial and empirical, Porta’s mathematics refers to concrete objects and sensory evidence, rather than to logical-deductive definitions. Napolitani accordingly described Porta’s (erroneous) proposal for a method to squaring the circle as sleight of hand. In Porta’s presentation it emerged as yet another segreto that had to be arranged in ways that merely appear to be credible, appeal to the senses, and create marvel. Generally the ways of Elementorum is foreign to contemporary discussions in the field: Accordingly both his editions were not commented on by the foremost mathematicians of his time (Napolitani 1990).