Skip to content
Lizely

Chain Reaction

Choose one source unit and watch a deterministic wave spread through nearby powered units on discrete ticks.

Privacy: your files never leave your device. All processing happens locally in your browser.

How to use

  1. 1.Inspect every unit's grid position and visible power. Power is Manhattan range, so count horizontal plus vertical steps without diagonal shortcuts.
  2. 2.Select one source unit by touch, click, or keyboard, then trigger the field. Newly reached units emit together on the next discrete tick.
  3. 3.Study the recorded tick groups if the wave stops, choose a different source, and try again. Clear five fields at 200 points each for exactly 1,000.

About Chain Reaction

Chain Reaction is a five-level trigger puzzle about predicting how one local event can spread across a field. Each experiment places several powered units on a fixed five-by-five grid. Every unit displays a power value from one to three. Select exactly one source and start the reaction. The source emits on tick zero. Any uncleared unit within that source's Manhattan range activates on the next tick, and every newly activated unit then emits its own wave one tick later. The process continues until every unit is cleared or no new unit can be reached.

This is not a domino placement puzzle. You do not build a path, spend pieces, or connect adjacent tiles before testing. The field is already populated and one selection launches the entire experiment. Distance can span empty grid cells, and a stronger unit may reach several targets at once. Multiple units activated on the same tick form one simultaneous frontier. Only that new frontier emits during the following tick. The central question is therefore which existing unit can start a directed cascade that eventually covers the whole field.

The simulation uses explicit deterministic rules. Range is Manhattan distance: count horizontal and vertical steps between two cells, with no diagonal shortcut. A source with power two reaches any uncleared unit at distance two or less. Candidate units are examined in stable board-list order, so the same trigger always produces the same tick groups. A unit activates only once. The Tick recorder lists every observed wave as T0, T1, T2, and later steps, while cleared units shrink and display the tick on which they reacted. This is computed result data rather than a decorative animation.

Clearing every unit awards exactly 200 points and unlocks the next experiment. Five full clears produce the exact maximum score of 1,000. A trigger that leaves active units earns no points, but it can be repaired: select a different source and run the field again. Repeating the identical failed trigger is deduplicated, so a double press does not consume another mistake. A second genuinely different failed source closes the run. When a corrected source succeeds after one failure, the failure record is cleared before the next level.

A practical strategy starts by reading power and position together. High power alone is not enough if the unit can reach only weak dead ends. Look for a source that reaches one or more useful relays. Then imagine the reaction in frontiers: mark the source as tick zero, identify every target inside its range for tick one, and repeat from only those newly reached targets. Branches are valuable when they cover separate regions. A remote low-power unit is often the hardest endpoint, so check which relay can reach it before committing to the trigger.

The five experiments progress from a short three-unit relay to longer fuses, a corner-to-corner handoff, a four-way bloom, and a final multi-branch surge. The grid size and rules never change. Difficulty grows through placement, power distribution, simultaneous waves, and directed reachability. Because the board is deterministic, players can compare a mental forecast with the exact recorded ticks and understand where an unsuccessful chain stopped. There is no random spawn, hidden probability, physics timing, or server response.

Pointer and touch play use native unit buttons. Tap a unit to select it, then press Trigger selected unit. Keyboard play is scoped to the reaction field: focus a unit, use arrow keys to move through the available units, press Space to select, and press Enter to trigger. Restart, Trigger, and Next experiment retain their normal button behavior when they hold focus. Every unit control is at least 44 pixels high, the five-column field stays within a 390-pixel viewport, and status updates are announced with live text.

Before a trigger runs, the page exposes only the product rules: unit positions, visible power values, and the player's current selection. It does not place a solution index, correct-source flag, future tick list, hidden answer, or success marker in visible text, accessibility labels, hidden fields, or data attributes. After the simulation, observed tick groups are displayed because they are now part of the result. The complete successful and failed trigger classifications are kept out of production level objects and verified only by an independent test oracle.

All five fields, power values, scoring rules, and propagation behavior are original product fixtures. They do not claim to model a chemical, nuclear, biological, electrical, or physical process. The word reaction describes an abstract discrete graph game. Independent tests recalculate each wave using separate code for every possible source, lock the complete success set for each level, prove every remaining source stops early, verify unit positions are unique, and check exact scoring, failure repair, deduplication, deadlock, restart equality, terminal freezing, spatial keyboard navigation, and invalid-input no-ops.

Everything runs locally in the browser. Source choices, tick records, mistakes, progress, and scores are not uploaded. No account, subscription, extra package, or network calculation is required. Use the game as a compact reasoning break, a visual introduction to directed reachability, or a way to practice separating simultaneous state changes into clear discrete steps.

Methodology & sources

Five original 5-by-5 fields use fixed unit cells and integer powers from one to three. A selected source forms tick zero. For each later tick, every uncleared unit within the Manhattan range of any unit in the immediately previous frontier activates simultaneously; candidates are processed in stable unit-index order. Propagation ends on full clear or an empty frontier. Independent literal tests implement a separate tick oracle for every possible source, lock complete success sets, prove every other trigger stops, and verify unique valid cells, exact 200-point awards and 1,000 completion, one-failure repair, success reset, identical-trigger deduplication, second-distinct-trigger deadlock, restart equality, spatial cursor ranking, terminal freeze, and atomic invalid operations.

Frequently asked questions

How is this different from the domino chain puzzle?
The domino game asks you to place limited adjacent pieces. This game starts with a populated field: you choose one source, and visible power ranges drive a directed multi-tick wave across empty grid distance.
What does a unit's power number mean?
It is the maximum Manhattan distance of that unit's outgoing wave. Add horizontal and vertical steps. Any uncleared unit inside that range activates on the following tick.
Can I fix a trigger that does not clear the field?
Yes. One failed source can be replaced with another. The same failed source is counted only once, while a second different failed source ends the run. A successful correction clears the failure history.

Related tools

Mini Games guides

View all