private void DrawChessBoard()
{
    Vector3 widthLine = Vector3.right * 8;
    Vector3 heightLine = Vector3.forward * 8;

    for (int i = 0; i <= 8; i++)
    {
        Vector3 start = Vector3.forward * i;
        Debug.DrawLine(start, start + widthLine);
        for (int j = 0; j <= 8; j++)
        {
            start = Vector3.right * j;
            Debug.DrawLine(start, start + heightLine);
        }
    }
}