Nikolas Ivanovitch Lobatchewsky was a mathematician who introduced the concept of non-Euclidean geometry to the public (remember that Gauss did not do this). His ideas were challenged due to the popularity of Kant’s Critique of Pure Reason, in which the idea of non-Euclidean geometry would be made absurd.

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