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
🌀

Closures and Iterators Sprint

What a closure captured, Fn or FnMut or FnOnce, lazy adapters that run one item at a time, filter, take and skip in order, and what position, fold and max return.

⏱️ 120s
▶ Log in to play

← Back to the arcade