The Chain Reaction game is a five-level browser puzzle in which one chosen source unit starts a directed Manhattan-distance wave that spreads across a populated 5×5 grid on discrete ticks until every unit is cleared or no new unit can be reached. Each experiment places several powered units on a fixed grid where every unit displays a power value from one to three. Selecting exactly one source and triggering it launches the entire reaction; there is no piece placement and no domino-style path building beforehand. The source fires on tick zero, every uncleared unit inside its Manhattan range activates on the following tick, and every newly activated unit then emits its own wave one tick later. Because the rules are explicit and deterministic, the same trigger always produces the same recorded tick groups. The complete Chain Reaction package contains five original experiments and a maximum reproducible score of exactly 1,000 points, with each fully cleared field contributing exactly 200 points. Independent tests recalculate each wave using separate code for every possible source, lock the complete success set for each level, and prove every remaining source stops early, so the published score cap is the real cap.
Power and Manhattan Distance
Powers of one, two, and three are the maximum Manhattan distance each unit's outgoing wave can travel. Manhattan distance is the sum of horizontal and vertical steps between two cells, with no diagonal shortcut. A unit at row 0 column 0 and another unit at row 2 column 1 are three steps apart: two steps down plus one step right, so a unit with power three reaches the target while a unit with power two falls one step short.
The range can span empty grid cells, so a strong unit in one corner of a 5×5 field can reach several distant targets without needing a chain of intermediate units. Distance is always measured between the unit's own cell and the target's cell, never through a shared neighbor. Diagonal neighbors such as row 0 column 0 and row 1 column 1 are distance two, not distance one, because you must move one step down and one step right to connect them. This single rule is the engine behind every chain, and reading it correctly is the first habit the Chain Reaction game rewards.
Worked example: a source at row 1 column 2 with power three is asked whether it can reach row 3 column 0. The horizontal distance is the absolute difference in columns, which is |2 − 0| = 2. The vertical distance is the absolute difference in rows, which is |1 − 3| = 2. The Manhattan distance is 2 + 2 = 4, which exceeds the source's power of 3, so the source cannot reach row 3 column 0 in a single wave. The same source can reach row 2 column 4 because |2 − 4| = 2 horizontally and |1 − 2| = 1 vertically, giving 2 + 1 = 3, exactly equal to its power. The formula, the substituted coordinates, and the resulting comparison all live inside one paragraph so you can repeat the same shape on any other pair of cells.
Tick Groups and Discrete Frontiers
Each turn in the Chain Reaction game is a discrete tick, not a continuous animation. The source unit you choose forms tick zero, and every unit it can reach activates on tick one as a single simultaneous group. Only that group emits during the following tick, which is tick two. The pattern continues: each new frontier is the only group that fires in the next tick, so the chain unfolds as a series of clean labeled steps rather than overlapping waves.
The board processes candidates in a stable unit-index order, so the same trigger always produces the same tick groups. This is what makes the simulation reproducible and what lets you compare a mental forecast with the exact result the game records. A unit activates exactly once, after which it shrinks and stamps the tick on which it reacted. The on-screen tick recorder lists every observed wave as T0, T1, T2, and later steps so you can read the full cascade back after the trigger has run, and those tick stamps are computed result data rather than a decorative animation.
A single tick can activate more than one unit at once, and those units together form the next frontier. Branches are valuable when they cover separate regions of the field, because each newly activated unit brings its own reach into the next tick. A remote low-power unit is often the hardest endpoint, so identifying which relay can finally reach it is the central puzzle the Chain Reaction game presents on every experiment.
| Tick | Who emits | What happens next |
|---|---|---|
| T0 | The chosen source unit | Every uncleared unit inside its Manhattan range forms the T1 frontier. |
| T1 | Every unit activated during T0 | Each one emits its own wave, and the combined new frontier becomes T2. |
| T2 onward | Only the previous frontier | Propagation continues until every unit is cleared or no new unit is reached. |
| Terminal | No new units reached | The chain stops, and any remaining uncleared units count as a failed run. |
How to Play the Chain Reaction Game
Open the Chain Reaction game and inspect the field before you touch the trigger button. The 5×5 grid is already populated with powered units, and every unit shows a power value from one to three, so the first job is purely visual: read each position and each power number together, then look for a source whose reach covers one or more useful relays rather than only weak dead ends.
- Inspect every unit's grid position and visible power. Power is Manhattan range, so count horizontal plus vertical steps without diagonal shortcuts.
- Select one source unit by touch, click, or keyboard, then trigger the field. Newly reached units emit together on the next discrete tick.
- 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.
Before the trigger runs, the page exposes only the product rules: unit positions, visible power values, and the player's current selection. There is no solution index, no correct-source flag, no future tick list, and no hidden answer in any visible text, accessibility label, hidden field, or data attribute. The board remains a clean planning surface until you commit to a trigger.
If you are using a keyboard, focus a unit and use the 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 so the controls are reachable without a mouse.
Scoring, Failure Repair, and the 1,000-Point Route
Clearing every unit on a field awards exactly 200 points and unlocks the next experiment, and five full clears at 200 points each produce the exact maximum score of 1,000. A trigger that leaves active units earns no points, but it can be repaired rather than immediately lost. Select a different source and run the field again, and the Chain Reaction game gives you one free repair because a single misstep should not waste an experiment.
The same failed trigger is counted only once, so a double press does not consume another mistake. A second genuinely different failed source, however, closes the run. When a corrected source succeeds after one failure, the failure record is cleared before the next level, so you start the next experiment with a clean slate. Repeating the identical failed trigger is deduplicated, which keeps the failure count honest and prevents accidental double-clicks from ending an otherwise recoverable run.
The Chain Reaction game keeps everything local in the browser. Source choices, tick records, mistakes, progress, and scores are not uploaded, no account or subscription is required, and there is no server-side calculation. Independent tests recalculate each wave using separate code for every possible source, lock the complete success set for each level, and prove that every remaining source stops early. The five fields, power values, scoring rules, and propagation behavior are original product fixtures, and the rules never claim to model any chemical, nuclear, biological, electrical, or physical process. Reaction here describes an abstract discrete graph game.
The Five Experiments in the Chain Reaction Game
All five experiments share the same 5×5 grid, the same power values from one to three, and the same tick rules. Difficulty grows through placement, power distribution, simultaneous waves, and directed reachability rather than through changing the underlying mechanics. The early experiment is a short three-unit relay that introduces the basic idea, while the final experiment is a multi-branch surge that demands a careful forecast of every simultaneous frontier at once.
| Experiment | Theme | What the trigger must solve |
|---|---|---|
| 1 | Short three-unit relay | Find a single source whose Manhattan range reaches the only useful relay. |
| 2 | Longer fuses | Chain weak units across empty cells where range has to be read precisely. |
| 3 | Corner-to-corner handoff | Bridge the diagonal distance with one well-chosen relay in the middle. |
| 4 | Four-way bloom | Trigger one strong unit that fans into several simultaneous branches on the same tick. |
| 5 | Multi-branch surge | Combine relays, blooms, and a remote low-power endpoint in one forecast. |
Because the board is deterministic, you can compare your mental forecast with the exact recorded ticks and understand precisely where an unsuccessful chain stopped. There is no random spawn, hidden probability, physics timing, or server response in the simulation, so every failed run teaches a reproducible lesson about which source could have reached further. Each experiment also acts as a checkpoint: a single full clear moves you on, and a strategic shortcut in the early levels leaves more room to read the longer fuses and the multi-branch surge at the end.