Pylos is a board game

Board game

A board game is a game which involves counters or pieces being moved on a pre-marked surface or "board", according to a set of rules. Games may be based on pure strategy, chance or a mixture of the two, and usually have a goal which a player aims to achieve...

 invented by David G. Royffe and published by Gigamic

Gigamic

Gigamic is a French seller of games. Their games include:* Gobblet* Pylos* Quarto* Quoridor...

. Two players are given 15 marbles each. They take turns to make a pyramid in a 4 by 4 square grid (note that 15 × 2 = 4 × 4 + 3 × 3 + 2 × 2 + 1). Simple rules allow them to save their marbles — if possible, instead of playing a new marble, a player may rise one of his already played marbles to a higher position, and if any move forms a line or 2×2 square of marbles the player's colour, the player may (and indeed must) remove one or two of his marbles from the board. The winner is the player who completes the pyramid.