I'm teaching my friend about CS, and I thought a good way to explain loop, time complexity, by asking a famous question in the QuanT world, calculate the square root of a given number with nothing but basic arithmetic methods.
Comparing square root methods - Brute force vs Babylonian method. An understanding of mathematical convergence, and time complexity - Gist is a simple way to share snippets of text and code with others.
I'm still dazzle by the elegant solution that mathematician found in 60AD (nearly 2000 years ago!!!!) Weren't they busy waging war?