Proposed by Chris Jefferson, Angela Miguel, Ian Miguel, Armagan Tarmin

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

Other board types, such as the Solitaire Triangle, also exist.