- Sourcery is a fantasy novel by British writer Terry Pratchett, the fifth book in his Discworld series, published in 1988.
- How the Square Root of 2 Became a Number (quantamagazine.org)
The ancient Greeks wanted to believe that the universe could be described in its entirety using only whole numbers and the ratios between them — fractions, or what we now call rational numbers. But this aspiration was undermined when they considered a square with sides of length 1, only to find that the length of its diagonal couldn’t possibly be written as a fraction.