What are the easter eggs you know about programming

Question

While surfing internet i found a python easteregg which is :

https://code.sololearn.com/ckoDlBkSezF8/?ref=app

what are the other easter eggs you want to suare with us for any language?

Answer 1

before any one say it also for python
write and run:

import this

Answer 2

python

import antigravity