An Infinite Universe of Number Systems - The p-adics seem to be a fanciful formalism of numbers. What’s interesting about it is that it provides a way to study an entire university of number systems.
A friend told me about Su Hui’s Star Gauge. It is is a matrix poem composed in the 4th century by the Chinese poetess Su Hui. The characters are arranged in a 29x29 matrix. The submatrices can be read in different directions, producing (apparently) 3000 poems.