Futoshiki is a board-based puzzle game, also known under the name Unequal. It is playable on a square board having a given fixed size (4x4 for example). The purpose of the game is to discover the digits hidden inside the board's cells; each cell is filled with a digit between 1 and the board's size. On each row and column each digit appears exactly once; therefore, when revealed, the digits of the board form a so-called Latin square.
A correctly filled square must satisfy the following three conditions:
1. The numbers in each line should not be repeated.
2. The numbers in each column should not be repeated.
3. If there are signs (arrows) on the field, then the condition must be met. (One number is smaller than the other).