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

📐

Cross-Entropy & Gibbs' Inequality Sprint

Compute H(P,Q) directly, then judge whether D(P||Q) can dip below 0 -- it can't, and Gibbs' inequality is why.

⏱️ 90s

▶ Log in to play

← Back to the arcade