https://github.com/cosmologicon/pywat
Here's another one. Compare "x = 256; y = 256; x is y" with "x = 257" (enter) "y = 257" (enter) "x is y" with "x = 257; y = 257; x is y". It makes a difference whether x and y are assigned on the same line or not. From here:
http://glasnt.com/blog/2016/05/28/on-language-oddities.html