Color Fill Flow — Connect Same-Color Dots
Connect each pair of same-colored dots with a flowing path. Fill the whole grid to win.
How to play
- Click a colored dot to begin a flow of that color.
- Click adjacent cells one at a time to extend the flow toward its twin dot.
- Flows can't cross — each cell holds only one color.
- Fill the entire grid (and connect all pairs) to win; 'Clear' resets paths.
Each color has two dots. Click one dot to start a flow, then click neighbouring cells one step at a time to snake a path of that color across to its twin. Flows can't overlap, and you win when every cell on the board is filled with color.
How it works
Color Fill Flow presents a grid with several pairs of colored dots. Your task is to draw a flowing path connecting each matching pair of dots. Two rules apply simultaneously: paths of different colors may not cross, and every cell on the grid must be covered by a path by the time all pairs are connected.
This is essentially the same constraint problem as Number Link but presented with colors and a flow aesthetic. The dual constraint — connect all pairs AND fill all cells — is what makes puzzles non-trivial. A direct shortest-path solution for each pair almost always leaves empty cells stranded.
Work from the most constrained pairs first: pairs hemmed in by corners or neighboring paths have very few routing options, so locking them in early prevents conflicts. As each colored path is fixed, it acts as a barrier that constrains the routing choices for all remaining colors.
The game scales well from small 5x5 grids suitable for beginners to large 9x9 grids for experienced players. It is an excellent spatial planning challenge and a popular mobile puzzle genre.
Worked example
Fill a 5x5 grid with four color pairs
- Start with the color pair separated by the narrowest corridor — they have the fewest valid paths.
- Trace that path; it now divides the remaining board into distinct regions.
- Choose the next color that is fully contained within one region and connect it there.
- Continue connecting constrained colors, always filling walled-off regions before opening new areas.
- The last color will naturally fill remaining empty cells if earlier paths were routed thoughtfully.
All dots connected, all cells covered, no paths crossing.
Common mistakes to avoid
- Connecting easy adjacent pairs with short straight paths first, which can strand empty cells that no remaining color can reach.
- Drawing paths that completely surround a dot of a different color, cutting off its only route to its partner.
- Declaring victory as soon as all dots are connected without checking whether any cells remain uncovered.
Key terms
- Flow path
- The drawn route connecting one colored dot to its matching partner.
- Full board constraint
- The requirement that every grid cell must be covered by exactly one flow path when all pairs are connected.
- Region
- A section of the board isolated from other sections by already-drawn paths; each remaining color must route within its accessible region.
Frequently asked questions
- Do I have to fill the whole grid?
- Yes — a true solution connects every pair AND covers every cell with a flow.
- How do I restart one flow?
- Click 'Clear' to wipe all paths, or click the tip cell again to pause and re-route.