In Fillomino, the goal is to place a number in every cell in order to complete the puzzle according to the rules (see Rules tab). To play, you can click on a cell or move around with the arrow keys, then enter a digit.

• Use the mouse left-click to move the cursor to a desired cell.
• Once selected, arrow keys can be used to move around the canvas.
• Use digit keys 1-9 to enter a single-digit value
• Use letter keys A-Z for double digit values 10-35, respectively.
• Bold digits are the initial puzzle values, and can not be overwritten.
• You can also left-click on an existing number and "drag" it to other cells to overwrite their value with its value.
• Similarly you can press and hold the shift key, then use the arrow keys to move around the board to propagate the current number to other cells.
• To remove an entered number, you can right-click the cell, or press the back space to clear.
• You can also drag a cleared cell with the mouse left-click or shift- and arrow keys to clear out new cells.
• For visualization of numerical boundaries, you can left-click on a cell border between cells to make a note of expected numeric separations, though no error checking is made.
• You can right-click to remove drawn borders, but not calculated ones.
• Once on a boundary, you can shift- arrow move to add more borders. You can also drag left-click to draw borders, or drag right-click to clear borders.

In Assist Mode (0), the default, only the existance of errors or incomplete numbers is indicated. In Assist Mode (1), the number of errors and incomplete numbers is indicated, see game rules. In Assist Mode (1) or higher, each numbered square is given a different color to visually guide the solver in searching for room completions. In Assist Mode (2) errors are highlighted with red digit colors. Additionally, borders are drawn between different digit cells and around rooms as they are completed. In some cases the solve difficulty will greatly decrease in Assist Mode (1) or higher, so select depending upon the level of challenge desired. The game border will turn green if the grid is completed without error. You can click the "undo" button on the bottom of the page to undo previous moves.

Below, enter puzzle code (0-0) for one of a list of pre-defined puzzles, or a puzzle descriptor (see "Puzzles" tab). Puzzle code 0 shows an example completed puzzle that can be helpful. The following puzzle codes have demos, which will walk you through a solve to help you on the path to mastery: []).

Fillomino (フィルオミノ) is a classic Japanese logic puzzle published by Nikoli. In Fillomino, the board begins with some pre-set cells with numbers in them. These numbers can not be modified, but indicate the size of a "room" or polyomino (collection of squares) containing only those numbers. For instance, a cell with '9' on it must be combined with eight other squares of any shape - connected horizontally or vertically - all containing the number 9. The full set of rules below relate to those numbers and how to complete the puzzle.

1. Pre-set number cells can not be modified, and must be part of a room with that number of squares joined horizontally or vertically.
2. Collections of like-numbered digits cannot border other collections of the same digit. For instance, a legal collection of '4' cells cannot border another collection of '4' cells. Put another way, a collection of 5 or more adjacent '4' digits is illegal. If in assist mode 2, the canvas will indicate this with red-colored digits once the collection is in error. Similarly a collection that has no chance of growing as large as needed to make it of legal size turns digits red. It is legal to connect two rooms with the same number at a diagonal point, i.e. not connected horizontally or vertically.
3. All squares must have a number before the puzzle can be solved.
4. Not all eventual rooms will have pre-set number cells within them. The solver must often infer what value the cells must have in order to complete the puzzle without error.

Puzzles can be invoked by either a numerical entry from 0-0, or through a character description of the puzzle itself, entered into the Display form on the 'Game Play' tab. The numbered puzzles are hand-crafted of varying difficulty, roughly easy to hard. Puzzle 0 shows a completed correct puzzle.

To describe a puzzle, the character string must be of the form: "WxH:<digit-descriptor>", where W is a number indicating the width of the grid, and H the height. The digit descriptor is a list of the pre-defined digit contents, from left to right, then top to bottom. Blank cells are represented with a '-' character. To assist in the definition of a sparse board, a combination of b consecutive blanks can be represented with a lowercase letter from 'a' to 'z', corresponding to 1 to 26 consecutive blanks. Digit values greater than '9' should be represented with capital letters 'A' to 'Z' representing 10 to 35. A dot '.' can be used as a visual separator, for example between rows. An example descriptor is as follows for entry 1: 'descr'.

For Fillomino there are 1 demo puzzles that can be helpful to walk through solving methods. They are puzzle codes []. Enter them in the Game Play tab with the code number and there will be added a demo panel to help with the solve.

This playground was written using javascript and is available open source. All code is checked into the github repo at ohmec/puzzles. Feel free to file bugs there!