I started a CodeWars kata in Python, just two days ago, related to code golf.
Task: Given two congruent circles a and b of radius r, return the area of their intersection rounded down to the nearest integer, in less than 128 chars.
Has to be a one-liner.
Version: Python 3.6
External libraries: You may import NumPy as an external library.
This is the closest I could come (129):
from math import*;circleIntersection=lambda a,b,r:r*r*(lambda h:h<1and acos(h)-h*(1-h*h)**.5)(hypot(b-a,b-a)/r/2)//.5