Col is a pencil and paper game, specifically a map-coloring game, involving the shading of areas in a line drawing according to the rules of Graph coloring. With each move, the graph must remain proper (no two areas of the same colour may touch), and a player who cannot make a legal move loses. The game was described and analysed by John Conway in On Numbers and Games. Games that can be played with only pencil and paper: Battleship was played as a pencil and paper game, long before Hasbro came out with a board game version. ... Several map-coloring games are studied in Combinatorial game theory. ... A 3-coloring suits this graph, but fewer colors would result in adjacent vertices of the same color. ... A 3-coloring suits this graph, but fewer colors would result in adjacent vertices of the same color. ... John Horton Conway (born December 26, 1937, Liverpool, England) is a prolific mathematician active in the theory of finite groups, knot theory, number theory, combinatorial game theory and coding theory. ... On Numbers and Games is a mathematics book by John Horton Conway. ...

Example game

In the following game, the first of the two players is using red, and the second is using blue. The last move in each image is shown brighter than the other areas. Red is any of a number of similar colors evoked by light consisting predominantly of the longest wavelengths of light discernible by the human eye, in the wavelength range of roughly 625–750 nm. ... This article or section does not cite any references or sources. ...

The starting graph:
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The first player may colour any of the areas to begin. However, the region around the outside of the graph is not included as an area for this game.

After the first move:
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The second player now colours a white cell. As no areas are currently blue, any white cell is allowed.

Two moves in:
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At this point, the requirement that the graph be proper comes in to effect, as a red area must be made which does not touch the existing one:

Once the third region is coloured:
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Note that areas only count as touching if they share edges, not if they only share vertices, so this move is legal.

The game continues, players moving alternately, until one player cannot make a move. This player loses. A possible continuation of the game is as follows (with each move numbered for clarity):

Game over:
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In this outcome, the blue player has lost.

Snort

Snort uses a similar partisan assignment of two colors, but with the anticlassical constraint: neighboring regions are not allowed to be given different colors. Coloring the regions is explained as assigning fields to bulls and cows, where neighboring fields may not contain cattle of the opposite sex, lest they be distracted from their grazing.