Diagonal

Diagonal is a 2004 game by Cerrato Luca, published at Fogliaccio degli Astratti #23.

The game is played on an 8x8 board, initially empty.

Rules:

• On her turn, the player drops a friendly piece on an empty square
• After her move, the player scores as many points as the number of their pieces in the completed diagonals where the current piece belongs
• a single piece color in a diagonal does not score
• When the board is full, wins the player with highest score 

in this position, if Black plays [1] the score is 3 points
while if it was White playing at [1], the score is 3+3=6 points

Cerrato also proposes a variant, Diagonal Plus:

• Initially, players drop a number of neutral pieces on board
• These pieces are labeled with positive (bonus points) or negative (malus points) numbers
• Bonus and malus points cannot be placed on the same diagonal.
  
• For the 8x8 board, it is suggested to use: two pieces +2, one piece +3, one piece -2
• It is forbidden to complete a diagonal using only neutral pieces (besides the dropped piece)
• The scores should include the bonus/malus points besides the standard diagonal points