PlusMinusOne is a simple roll-and-write game in which each player is provided with a scoring sheet and a pen. After an initial roll of dice, the players in turn roll in turn one or two additional dice and write the value of one die or the sum of two dice in a cell of a scoring grid.
Players are only allowed to fill in cells that are adjacent to already marked cells and only if the value of the two cells are identical or differ by plus or minus one.
At the end of the game, the players receive one point for each cell that contains a number matching the position of the cell within its column or its row and one point for adjacent cells with identical content. Rows and columns without matching cells (i.e., a row N without any cell marked N) result in minus points, and the players are also penalised for every turn in which they are unable to mark a cell.
—description from the designer