Quick steps to get started
Swipe or draw one continuous line that passes through every block without lifting your finger or mouse.
You must fill every block in one go; backtracking isn’t allowed.
If a puzzle feels too complex, tap the hint icon to reveal part of the solution and it’s free.
s you complete puzzles, higher difficulty levels unlock more challenging puzzles.
What's it all about?
Sharpen your mind with a connect-the-block-style one-line brain training puzzle game. A simple but addictive one-line puzzle game that’s completely free to play. Your brain becomes more active the more you play. During your commute, before you sleep… enjoy downtime with brain training. The rules are extremely simple. Just fill in all of the blocks using only one line. Use hints for puzzles that are too hard to solve. Hints are also free, of course.
Our player, ratings, and related picks
Play The Fill free on CubicRubik in our puzzle collection. We host the game in a fast browser player, keep your recent plays and favorites on our site, and show related titles so your next session is one click away.
Unlike bare embed pages, CubicRubik adds ratings, category context, how-to steps, and curated related games around The Fill—so you get discovery and guidance, not only a third-party frame.
Quick answers before you play
Platforms & genres
