VEX is a high-performance expression language used inside SideFX Houdini. It looks a lot like C, and it is the primary way artists and technical directors write custom logic to manipulate geometry, create procedural effects, and build tools. You write VEX snippets inside Wrangle nodes (most commonly an Attribute Wrangle set to run over Points, Vertices, Primitives, or Detail), this can be changed on the node Parameters Interface anytime.
This tutorial is written in the classic "Learn X in Y Minutes" style: one giant block of valid, heavily-commented VEX code that you can read top-to-bottom like an article. You do not need any prior programming or math experience. Every concept is explained from scratch with multiple examples before moving on.