Jollywatt blog ⊕ portfolio

French verb conjugations quizzer

An app to help you practice conjugating French verbs. 🇫🇷 Read more


Basic general relativity with Julia

Four years after I took general relativity, my professor asked me to send him an old animation I had made during his course showing parallel transport of vectors around a line of latitude on the sphere. Actually, I wasn’t the one who had made it (though I was flattered that... Read more


Defining Entropy with a Composition Law

My favourite characterisation of (information) entropy with a ‘composition law’, and a uniqueness proof. Read more


Daylight Hours: A spherical geometry problem

How many hours are there between sunrise and sunset? The Earth’s tilt makes this a fun geometry problem… Read more


Billiard geometry: Visually solving elastic collisions

A neat relationship between elastic collisions and ellipses. Read more


Geometric Algebra for Special Relativity and Manifold Geometry · PDF

Master’s thesis in mathematical physics. Read more


World Flags Quizzer

A game to teach you world flags. 🇨🇳🇮🇳🇺🇸🇮🇩🇵🇰🇧🇷🇳🇬🇧🇩⋯ Read more


A Simple Example of a Connection With Torsion

While learning general relativity as an undergrad, I was uneasy with the idea of torsion of an affine connection. Familiar phrases like “torsion measures how a frame twists as it undergoes parallel transport” seemed too lofty to serve as a helpful mental model. The following example is one which gave... Read more