Skip to content
Free public beta until December 4, 2026: every course is open, no card needed. After that, the first chapter of each course stays free and full access is a one-time $39 ($19 for up to 100 founding members chosen for helpful feedback). Your progress is kept. How the beta works
✨

?., Patterns and Lambdas

?. and ?? and ??=, first-match switch arms with < and <=, and what a lambda in a loop really captured.

🎯 5 in a row 🚫 no clock
▶ Log in to play

← Back to the arcade