LineLock

Inspiration

Daily games on Reddit work best when they are fast, social, and slightly competitive. We were inspired by the rise of simple one-stroke “connect the dots” puzzles that circulate on platforms like LinkedIn but noticed that they are usually static, non-social, and solved once and forgotten.

Reddit is different. People don’t just solve puzzles here they debate them. LineLock was inspired by the idea of turning a familiar puzzle into a community-driven daily ritual, where Redditors don’t just play the game, but actively shape tomorrow’s challenge through discussion and voting.

What it does

LineLock is a daily, one-stroke connect-the-dots puzzle built for Reddit.

Each day:

• All players receive the same puzzle.
• Players draw a single continuous path to connect all dots while obeying a set of constraints (e.g. no diagonals, no crossing lines, fixed start/end).
• After completing the puzzle, players unlock the ability to vote on constraints for the next day’s puzzle.

The most upvoted constraints are applied to tomorrow’s game, making the community an active participant in designing future challenges. This creates a loop of daily play, discussion, and shared ownership.

How we built it

LineLock was built using Devvit Web and Reddit’s Interactive Posts system.

• The UI is mobile-first and optimized for touch gestures.
• The core game logic validates one-stroke paths and enforces daily constraints.
• Daily puzzles reset automatically, ensuring a shared experience for all players.
• Constraint voting is implemented using Reddit-native interaction patterns, encouraging comments and discussion.
• The game is designed to be lightweight, fast, and playable in under a minute.

The focus was on polish, clarity, and seamless integration into Reddit’s ecosystem rather than complex infrastructure.

Challenges we ran into

One of the main challenges was designing constraints that meaningfully change the puzzle without making it impossible or frustrating. We had to carefully balance difficulty, clarity, and replayability.

Another challenge was ensuring the game felt natural on mobile devices, since most Redditors play from their phones. Drawing accuracy, visual feedback, and error handling required multiple iterations to get right.

Finally, designing a social loop that encourages discussion—without overwhelming players—required us to keep the interface minimal while still making community participation feel impactful.

Accomplishments that we’re proud of

• Creating a daily game mechanic that feels native to Reddit.
• Turning comments and voting into a core part of gameplay rather than an afterthought.
• Designing a puzzle that is simple to understand but deep enough to generate discussion.
• Delivering a polished, mobile-friendly experience that works seamlessly inside Reddit posts.
• Building something that encourages healthy debate (“Is this puzzle even solvable?”) rather than just silent play.

What we learned

We learned that the strongest Reddit games don’t fight the platform—they embrace it. Games that leverage comments, upvotes, and shared daily experiences naturally generate engagement.

We also learned that simplicity scales better than complexity. A small mechanic, when combined with social input and daily variation, can outperform much larger systems.

Finally, we gained a deeper appreciation for mobile-first design and how critical frictionless interaction is for daily engagement.

What’s next for LineLock

Next, we plan to:

• Expand the constraint system with community-suggested rule types.
• Leaderboards.
• Explore long-term progression features such as streaks and historical puzzle archives.
• Integrate with Reddit’s developer programs to sustain and grow the game post-hackathon.

LineLock is designed to grow with its community—and we’re excited to see how Reddit shapes it next.

Built With

• axum
• postgresql
• react
• rust
• sqlx
• typescript