Pierre de Fermat is considered to be the greatest mathematician of the seventeenth century. He is known for his work in number theory and his last theorem, which has caught the attention of many mathematicians and other challengers. He also created the Fermat primes, which have later been shown not to be primes. Gauss was not interested in proving his last theorem.
Becca Hirsbrunner photographed this fabulously constructed Z proportions letter. Interestingly, every element but the diagonal bar can be rationalized.