Filling / Fillomino
Can equal regions touch in Filling?
A connected group of the same digit must contain exactly that many cells. Equal digits touching along an edge become one region. Diagonal contact alone does not join regions.
Worked example
Two neighbouring 2s already make a complete region. Adding a third 2 along an edge makes an invalid three-cell region of 2s.
What to check on your board
Apply the rule above to your current board, then verify the remaining puzzle constraints. The example explains a local deduction; it is not a solution to every randomly generated board.
Checking your next move
Count an equal-digit region by following edge contacts, not by visually grouping nearby cells. Once the region reaches its required size, another matching digit on its boundary would enlarge it illegally. Recount after joining two partial groups: their sizes add together.
Using this reference
For Filling / Fillomino, read the rule and the worked example together before opening the game. Separate what the rule explicitly requires from what only seems likely on the current board. A useful next move is one you can explain from the visible constraints, not merely a pattern that looks familiar.
If you get stuck, isolate a smaller part of the position and list what is still possible there. After a move, check the affected rows, regions or connections again. The reference explains the documented rules; progress, controls and save behavior belong to the linked game.
Read the developer’s manual ↗ · Open the developer’s browser version ↗
Manual inspected: · Simon Tatham & contributors · MIT