Python Craft Ladder

Reading Python, and even understanding it, is not the same skill as writing it — that skill only forms when you produce code yourself and something honest checks the result. This module is the platform's first graded practice: you write Python right here in the browser, run it, and have it tested, and because everything runs in Pyodide, a full Python compiled to WebAssembly, your code never leaves your machine. Each exercise is a three-panel workspace with instructions on the left, a code editor in the middle, and output plus test results on the right, where Run checks the visible tests you can read, Submit also grades a set of hidden edge cases so that hard-coding the shown answers cannot pass, and the reference solution unlocks once you succeed. Work down the ladder: each rung is a small, self-contained piece of Python craft with no data files to load.