'Noughts and Crosses', or 'Tic-tac-toe' as it is known in America or 'Xs and Os' in Ireland, is a game for two people that only requires a pen/pencil and paper. The board or grid, which is drawn onto the paper, consists of a square that is crossed by two vertical and two horizontal lines. In total, there are nine small squares: three on the top line, three in the centre and three more on the bottom line.

Each player chooses whether to be 'noughts' (O) or 'crosses' (X) and take turns to draw a cross or a circle in a square on the grid. The winner is the person who manages to draw three of their symbols in a row, either vertically, horizontally or diagonally.

The game can be traced back to ancient Egypt (c. 1300 BC), where players etched lines into tiles or slates. In the first century BC, the Roman Empire played a similar game called 'terni lapilli', meaning "three pebbles at a time". Rather than filling the grid with symbols (or pebbles), players only had three pebbles, which they continually moved around the grid until someone gets three in a row.

The British name, 'Noughts and Crosses', first appeared in 1858, in an issue of the scholarly journal, 'Notes and Queries'. The term 'tick-tack-toe' was first used in 1884, in reference to a game in which the players shut their eyes and pointed to a numbered grid. The number they pointed to was their score. It was not until the 20th century that 'Tic-tac-toe' became an alternative name for 'Noughts and Crosses'.

More Info: en.m.wikipedia.org