Starting from the top-left, turn the whole board one colour
| Tap a colour | Change your territory to it and absorb matching neighbours. |
| New game | Generate a fresh board. |
Flood Fill starts you in the top-left corner of a grid of coloured tiles. Pick a colour and your territory changes to it, absorbing any neighbouring tiles that already match. Keep going until the whole board is a single colour, and do it before your limited supply of moves runs out.
It looks like a colour-matching game and behaves like a graph problem. Your blob grows by absorbing whatever it touches, so the right move is rarely the colour you can see the most of. It is the colour that connects your territory to the largest new region, which is a genuinely different calculation.
Choose the colour that touches your blob most, not the one that covers the most board. Distant tiles of a colour do nothing for you this turn. What matters is how much new territory you absorb immediately, because that determines what you can reach next.
Push toward the far corner early. Growing outward in all directions looks efficient but leaves you finishing in the middle. Extending your reach toward the opposite corner opens up the whole board faster.
Think one move ahead. Sometimes taking a smaller gain now positions your blob against a large region you can swallow next turn. Because moves are limited, the two-move combination often beats the greedy single move.
Watch the move counter. Running out with ninety percent covered is the most common way to lose, so if you are behind schedule, prioritise big absorptions over tidying small pockets.
Your territory starts at the top-left corner and changes colour with you. Any adjacent tile of the new colour joins your territory.
Yes, which is the whole challenge. Covering the board is easy with unlimited moves.
Usually whichever colour touches your starting corner most, but thinking one step ahead often beats the greedy choice.
Boards are generated to be solvable within the move limit, though it may take good play.
Nothing at all. The whole of Flood Fill is built into the page itself, which is why there is no loading bar and no waiting before you can play.