Extra game details (tournament conditions)

Board Geometry

• The game board is 20 cells wide and 12 cells high.
• Players start in opposite corners, two spaces from each corresponding edge.
• The distance between the players' starting positions is 17 on the X axis and 9 on the Y axis.

Anatomy of a turn

Grid Game is essentially built of a grid of cellular automata. Each cell is it's own entity which follows a set of rules. The descriptions here are how they are understood by the user. E.g. "A Walker will travel left without changing it's value" instead of the software-orentated version "The cell will reduce it's value to zero and the cell directly to the west will increase by that value and inherit it's player".

The result is that every cell changes at the same time, at the end of the turn. The pieces move simultaneously.

Each turn is made up of three phases:

• Bot phase - The bot selected will be run for each player to determine their direction during the rest of the turn.
• Damage phase - Each piece with a positive value will damage all adjacent spaces (including diagonals) by it's own value. This works in both directions. Pieces with a value of zero or less are removed.
• Movement phase - Remaining Walkers will attempt to move in their player's direction. Unless they are prevented from doing so by a city or the edge of the map. Walkers convert to cities at this phase if they have a value of 10 or more.

The board is visually updated after these three steps have taken place.

Things that can stop a Walker walking during the Movement phase:

• They are at the edge of the grid, there are no cells for them to walk on to.
• The space they are trying to walk on to is a city (of either colour).
• The space they are trying to walk on to is also being walked on to by an enemy Walker (see below).

New walkers are spawned every 3 turns, in the cell adjacent to cities, in their player's direction.

Things that stop new Walkers spawning:

• It's not a spawning turn.
• The City is on the edge of the map and there's no cell in the direction they would spawn in.
• The space they would spawn on is occupied by a city.
• The space they would spawn on is occupied by an enemy Walker (see below).

Edge Cases

The steps above cover the operation of the came except for a few unusual cases:

Two walkers step on to the same space.

During the damage phase, if more than one Walker is due to step on to the came cell, a 'little fight' ensures.

• If they have the same value, both pieces are removed.
• If they have different values, the higher value is reduced by the lower value, and steps on to the contested cell. The cell with the lower value is removed.

A Walker spawns in a space with an enemy Walker.

When a piece spawns on top of an enemy space, a simpler 'little fight' ensues.

• No new walker is spawned.
• The existing walker has it's value lowered by 1.

One can fight 3

+-+-+-+
| |1| |
+-+-+-+
|4|1| |
+-+-+-+
| |1| |
+-+-+-+

The above situation (where the ones are red, the four is green) will play out in a slightly counter intuitive way:

• The 1s will each do 1 damage to the 4, It will survive but be reduced to a value of 1.
• The 4 will do 4 damage to each of the 1's, they will all be destroyed.