Hi, I'm Mark.

I work in finance and have a habit of going down rabbit holes — usually involving a Python notebook, a pile of statistics, and a question that seemed simple until it wasn't. This blog is where those rabbit holes get written up.

The aim is always to explain things from first principles: no hand-waving, no assumed knowledge, just a patient walk through the reasoning with as many graphs as it takes. If you've ever wondered why we use log returns, or why tennis is scored the way it is, you're in the right place.