Fillomino (BrainBashers)

Fillomino is a region-dividing puzzle. When it is solved, the grid is split into groups of squares joined horizontally and vertically, and every square holds the number of squares in its group: a lone 1, pairs of 2s, three 3s together and so on. Some numbers are given at the start, and you fill in the rest. A given clue does not have to be the only one in its group; the site notes that two or more numbers can sit in the same group. Two separate groups of the same size cannot share a side, or they would merge into one larger group.

BrainBashers, Kevin Stone's puzzle site, posts an 8x8 and a 12x12 at Easy and a 16x16 at Medium every day, with a 20x20 weekly special. On the play page you pick a number from a column beside the grid and place it, and there are check, answer, print and restart buttons, an option to show mistakes and an optional clock. A help page has a walkthrough.

The puzzles change at midnight GMT or at the time zone you choose, and the date list keeps a few weeks of earlier days. No adverts, no account.

On a phone the 8x8 fits the screen. The 12x12 and 16x16 run past its right edge, so the larger grids are easier on a desktop or tablet.

It suits players who enjoy puzzles about shapes and areas more than about digits, even though it is written with numbers.