Stock Puzzle that presents a grid, and a bunch of elements that must be put in appropriate cells of the grid. There are usually constraints in which elements must or cannot be placed in the same rows, in the same columns, in the same diagonals, or touching on certain cell boundaries. The constraints may or may not determine a unique solution.
Unlike the sliding block puzzles (such as 15 Puzzle and Klotski) and Rubik's Cube, there are no restrictions on the way elements can be repositioned, except for possibly a few cells fixed at the start. Once you think you have figured out a solution, you're free to put any available elements where you think they ought to be. (The selection and availability of elements is non-random, too.)
Usually the grid is square, but it need not be quadrilateral; it could even have irregular boundaries.
- Cliff Johnson's games (The Fool's Errand, At The Carnival, 3 in Three) include several variations, such as unscrambling a picture, a map, or a crossword. Some used irregular grids.
- In Riven, the Fire Marble Puzzle is one of these. You must deduce where to place the six colored spheres in a 25x25 grid. Overlaps with Enter Solution Here, since you're just re-creating a map. The trick is gathering the information to make the map, then figuring out the precise positioning through trial and error.
- Mudball Wall in Logical Journey of the Zoombinis. The size of the grid and the number of variables goes up with the difficulty level. On "Oh So Hard" and "Very Very Hard", one variable doesn't correspond directly to its position in the grid, but a pattern still applies to it.
- The true ending of Nine Hours, Nine Persons, Nine Doors ends with such a puzzle. In the original DS release it's sudoku; in the later re-releases it's a number-base puzzle.
- In the video game adaptation of Callahans Crosstime Saloon, a simple marbles-in-the-holes puzzle is used to guard the ancient temple. The game then offers you a selection of more difficult puzzles that have nothing to do with the plot but hey, we designed the interface, might as well use it more than once ...