Mda

class Field
{
    public enum CellType { Empty, ColorR, ColorG }

    private CellType[,] Cells;
    private Size mCellSize;

    private int mWidth;
    private int mHeight;

    Graphics g;

    public Field(Panel P, Size FieldSizeInCell)
    {
        // проверить все на нул и нули
        // пока нет

        this.g = P.CreateGraphics();

        mWidth = FieldSizeInCell.Width;
        mHeight = FieldSizeInCell.Height;

        mCellSize = new Size(P.Width / mWidth, P.Height / mHeight);

        CreateFieldArray(); // сам
    }

    public void DrawField()
    {
        // тут нарисовать общий прямоугольник поля
        // пока нет

        for (int row = 0; row < mWidth; row++) {
            for (int col = 0; col < mHeight; col++) {
                this.DrawCell(row, col);
            }
        }
    }

    private void DrawCell(int row, int col)
    {
        CellType SomeCell = Cells[row, col];
        Color GradC = Color.Black;
        Color MainC = Color.Black;

        switch (SomeCell)
        {
            case CellType.Empty: MainC = Color.White;
            case CellType.ColorR: MainC = Color.Red;
            case CellType.ColorG: MainC = Color.Green;
        }

        // мда
        int X = row * mCellSize.Width;
        int Y = col * mCellSize.Height;
        LinearGradientBrush Br = new LinearGradientBrush(new Point(X, Y), new Point(X + mCellSize.Width, Y + mCellSize.Height), GradC, MainC);

        g.FillRectangle(Br, X, Y, mCellSize.Width, mCellSize.Height);
    }
}