Games and puzzles
Peg Solitaire (also known as Hi-Q) is played on a board with a number of holes. In the English version of the game, the board is in the shape of a cross with 33 holes:
OOO OOO OOOOOOO OOOOOOO OOOOOOO OOO OOO
Pegs ('X's here) are arranged on the board so that at least one hole remains. A number of different problems arise from Solitaire, e.g. finding a path from the initial to a goal state, or finding the shortest number of moves to a state where no more moves are possible.
Moves are draughts/checkers-like and are horizontal or vertical:
XXO -> OOX
The following is the classic 'central' version of the game:
Start: Goal: XXX OOO XXX OOO XXXXXXX OOOOOOO XXXOXXX -> OOOXOOO XXXXXXX OOOOOOO XXX OOO XXX OOO
The French version of the game has four extra holes:
OOO OOOOO OOOOOOO OOOOOOO OOOOOOO OOOOO OOO
The french version of solitaire cannot be completed starting with one hole in the middle, and ending with one peg in the center, without adding one extra peg during play (the player gets to decide where and when to place the extra peg).
Other board types, such as the Solitaire Triangle, also exist.