Jacob Bernoulli was one of the many prominent mathematicians in the Bernoulli family. He was an early proponent of Leibnizian calculus and sided with Gottfried Wilhelm Leibniz during the Leibniz–Newton calculus controversy.

Z Proportions
Becca Hirsbrunner photographed this fabulously constructed Z proportions letter. Interestingly, every element but the diagonal bar can be rationalized.