A color flood puzzle is a board game where you recolor a region from one corner outward, absorbing matching neighbors, until every tile shares a single color. The browser game Flood It takes that idea and freezes it: a fixed 5 by 5 four-color board, a deterministic expansion rule, and an eight-move minimum that has been independently proven by breadth-first search. Instead of random levels you get one specific fixture, three verified winning sequences, and exact 1,000-point scoring for finishing the board within the move limit. The initial region is just the top-left tile, which begins as Blue, and every legal recolor choice either grows the region or wastes a move, so the puzzle reads as a clean search over a small state graph rather than a guessing game. Understanding the rule and the eight-move ceiling is what separates a clean 1,000-point run from a locked one.
How Flood It Turns a Color Flood Puzzle Into an Audited Fixture
A color flood puzzle asks the player to recolor a colored grid by repeatedly choosing a color and converting the connected region that touches a starting cell. Most mobile and browser versions generate a random board each session, count the moves you spend, and score you by efficiency or speed. Flood It deliberately removes the randomness. It ships a single disclosed starting board, four labeled colors (Blue, Coral, Gold, and Teal), and scoring tied to a single numerical ceiling rather than a timer.
The general rule is shared with two well-documented references. The formal complexity paper by Arthur, Clifford, Jalsenius, Montanaro, and Sach (arXiv:1001.4420) defines a move as choosing a color and changing the monochromatic component connected to the top-left tile. Simon Tatham's Flood documentation independently describes choosing a square color to flood-fill the top-left region and finishing within a move limit. Those sources define the rule for the general problem. They do not supply Flood It's specific fixture, palette, score, controls, or failure policy, so the game is its own audited product rather than a re-skin of someone else's level pack.
Inside the Fixed 5x5 Board
The disclosed row-major starting board is laid out below. Each digit is a color ID, read left to right and top to bottom.
| Row | Color IDs (left to right) | ||||
|---|---|---|---|---|---|
| Row 1 | 0 | 1 | 2 | 3 | 1 |
| Row 2 | 1 | 1 | 3 | 2 | 0 |
| Row 3 | 2 | 0 | 2 | 3 | 1 |
| Row 4 | 3 | 2 | 1 | 0 | 2 |
| Row 5 | 1 | 3 | 0 | 2 | 3 |
The interface maps those IDs to four named colors with letter labels on every tile: Blue (B), Coral (C), Gold (G), and Teal (T). The tile distribution across the 25 cells is exact:
- 5 Blue tiles
- 7 Coral tiles
- 7 Gold tiles
- 6 Teal tiles
Every row is distinct, so no row is a copy of another, and the layout intentionally mixes the colors so the controlled region must bend around the board rather than flood in a straight line. Because the starting board is fixed rather than randomly generated, the puzzle's behavior can be audited exactly rather than depending on an unrecorded random seed. Restart always restores this same arrangement, and the controlled region is outlined so expansion is not communicated by color alone, which keeps the board readable for players who do not rely solely on hue perception.
How to Play Flood It Step by Step
The rules are simple enough to fit on a napkin, but the search is tight enough that every move matters. Follow this sequence from a fresh run.
- Start from the outlined top-left tile, which begins as Blue, and pick one of the three other colors (Coral, Gold, or Teal). The entire monochromatic region connected to that tile recolors to your choice, and any orthogonally adjacent tiles already showing that new color join your region.
- Continue picking colors, one per move, while watching the outlined region grow. Only horizontal and vertical neighbors count for flooding; two tiles that touch at a corner look close but stay separate.
- Use the four large color buttons under the board, press 1 through 4 to pick Blue, Coral, Gold, or Teal directly, or move the cursor with the arrow keys and press Space to choose.
- If a color turns out to be a weak choice, press Delete or Backspace to undo the latest selection. The undo replays the remaining color history against the original board, so it never depends on a hidden snapshot of intermediate states.
- Repeat until all 25 tiles form a single connected monochromatic board. Choosing the region's current color is disabled because it would not change the board and is not a meaningful standard move.
- When the board looks solved, choose Check board or press Enter. A monochromatic board checked at or before move eight earns exactly 1,000 points; any other outcome follows the two-strike contract described below.
A concrete transition anchors the rule. The initial controlled region is only cell 0, which is Blue. Choosing Coral recolors that tile and connects it to the Coral tiles immediately to its right and below, then continues through their orthogonally connected Coral neighbors. The controlled indices become 0, 1, 5, and 6. A separate Coral tile elsewhere on the board stays outside the region until a later expansion reaches it.
Three Verified Eight-Move Winning Routes
The eight-move ceiling is not a guess. An independent breadth-first search treats each complete board coloring as a state, applies each of the three colors different from the current top-left color, performs an independently written flood operation, and visits each distinct board only once. That search exhausts 415 reachable boards and finds no solved board at depths zero through seven. The first monochromatic board appears at depth eight.
A second independent enumeration then checks every legal color sequence of exactly eight moves and identifies three minimal winning sequences. Mapping the numeric IDs back to the interface color names:
| Sequence | Step-by-step colors | Length |
|---|---|---|
| 1-0-2-3-1-0-2-3 | Coral, Blue, Gold, Teal, Coral, Blue, Gold, Teal | 8 |
| 1-3-2-1-0-2-3-1 | Coral, Teal, Gold, Coral, Blue, Gold, Teal, Coral | 8 |
| 1-3-2-3-1-0-2-3 | Coral, Teal, Gold, Teal, Coral, Blue, Gold, Teal | 8 |
Flood It accepts all three verified routes; it does not lock play to a single memorized answer. Any other eight-move sequence either fails to flood the board or wanders into a state where the remaining moves cannot recover, which is exactly what the breadth-first search and the sequence enumeration independently demonstrate.
Check Board, the Two-Strike Contract, and the 1,000-Point Score
The Check board action is where most color flood puzzle interfaces get vague. Flood It uses a clear two-strike contract instead of a single pass/fail moment:
- If you check before move eight and the board is still unsolved, the attempt is reported as incomplete and no mistake is added. Early inspection is free.
- The first time you check at move eight or later and the board is still unsolved, the game records one mistake but keeps the board and Undo active. You can repair the run by undoing one or more colors and choosing a stronger sequence.
- The second time you check at move eight or later with an unsolved board, the run deadlocks. Color choices, cursor movement, undo, and repeat checks no longer change state. Only Restart recovers.
- A monochromatic board checked at or before move eight earns exactly 1,000 points and freezes the run as a terminal completion.
The 1,000-point score is exact. There is no speed bonus, no move deduction for finishing under eight, no random modifier, and no hidden partial credit. Completion and deadlock are both terminal, which prevents score farming and gives automated browser checks a stable result to assert against.
Controls, Undo, and Accessibility
Pointer and touch play is handled by four large color buttons below the board, sized to fit a 390-pixel viewport without horizontal scrolling. Keyboard play is complete: arrow keys cycle the color cursor, Space selects the highlighted color, the number keys 1 through 4 pick Blue, Coral, Gold, or Teal directly, Delete or Backspace undoes the latest color, and Enter triggers Check board. Repeated keydown events are ignored so holding a key cannot accidentally burn several moves.
The move history is deliberately visible. Each selection appends one color letter, and the native buttons expose color names, current-color state, and keyboard selection to assistive technology. All rules and state transitions run locally in the browser; the game uploads no board history, requires no account, calls no remote game service, requests no device permission, and introduces no package dependency. A 1,000-point result only certifies that this one disclosed fixture was completed within its proven minimum limit; it does not measure intelligence, vision, or attention.
For a different starting angle on the same fixture, see the Flood It 5x5 no-download guide.
For a deeper look, see Four Color Theorem Game: Five Maps, Proven Minima.