namespace Day3;

public record Point2D(int X, int Y)
{
    public IEnumerable<Point2D> SurroundingAndSelf()
    {
        for (var y = -1; y < 2; y++)
        {
            for (var x = -1; x < 2; x++)
            {
                yield return new Point2D(X + x, Y + y);
            }
        }
    }
}

public abstract class Token
{
    public Point2D Position { get; }

    protected Token(Point2D position)
    {
        Position = position;
    }
}