Signal Relay
Turn the conduits to link the source to the sink before corruption spreads.
How to Play Signal Relay
- Tap a conduit tile to rotate it a quarter turn.
- Build an unbroken path from the source to the sink to complete the link.
- Corruption spreads while you work — rotating a corrupted tile purges it and buys integrity.
Controls
| Keyboard | WASD to move the marker, arrow keys to turn it |
|---|---|
| Touch | Tap a conduit to turn it, or drag across several |
Tips
- Trace backwards from the sink. Working from the source wastes turns on the decoy branches.
About Signal Relay
Rotate conduit tiles to route a signal from source to sink. Corruption spreads across the board while you think, and turning a corrupted tile purges it. It runs directly in your browser with no download or sign-up, on desktop and mobile alike.
Design notes: how Signal Relay was built
A pipe is a four-bit mask — north, east, south, west — and rotating it is a bit rotation: ((msk << k) | (msk >> (4 - k))) & 15. Connectivity is then a plain breadth-first search from the source, re-run across all twenty-five cells on every single rotation. Recomputing the whole board is wasteful on paper and free in practice at this size, and it removes the entire class of bug where an incremental update leaves a stale connection behind.
The displayed rotation and the logical rotation are kept in separate variables. The logic uses a monotonically increasing turn count masked to two bits; the sprite uses a floating angle that keeps climbing. Sharing one value makes the pipe visibly snap backwards every time it wraps from the fourth turn to the first, which looks like a bug even when the board is correct.
Boards are generated by walking one guaranteed-solvable path from source to sink column by column, then filling the remaining cells with weighted random decoys. No backtracking and no solver — the solution is laid down first and the puzzle is built around it, which is the cheap way to guarantee that every board can actually be finished. Corruption never spreads into a cell carrying live signal, which quietly makes keeping a circuit lit a defensive move.
More of these in the dev notes.
Frequently Asked Questions
Is every board in Signal Relay solvable?
Yes. Each layout is generated from a real path first, then scrambled, so a solution always exists.
What does the pink hatching mean?
That tile is corrupted and draining your integrity. Rotating it clears the corruption.
How do you play it on a phone?
Tap a tile to turn it, or drag across a row to turn several in one motion. No keyboard needed.
Browse every game on Neon Arcade · read the dev notes behind them