...Each challenge is a miniature kata where you implement types that transform other types—parsing strings, inferring tuples, mapping unions—without writing any runtime code. Problems are arranged from warm-ups to brain-twisters, letting developers build intuition about distributive conditional types, inference in extends, variance, and other corner cases of the type system. The repository includes tests for each puzzle so you get immediate, compiler-driven feedback when your solution is correct. As a result, it doubles as both training material and a living reference for advanced patterns used in real libraries. ...