A lovely animation explaining Hilbert's Infinite Hotel Paradox which hurt my head back at university: https://www.youtube.com/watch?v=Uj3_KqkI9Zo /via @kottke
Writing tests is great, but a static type system is like a built-in test suite that catches all the ridiculous, pointless problems you waste time on every day, so that you can focus on the interesting ones.
– Tom Stuart on static typing in Ruby