static void TestValidityChecker()
{
for (int i = 0; i < maxNum; i++)
{
Console.WriteLine($"Col {i}: {s.ColumnValid(i)}");
Console.WriteLine($"Row {i}: {s.RowValid(i)}");
Console.WriteLine($"Square {i}: {s.SquareValid(i)} ");
Console.WriteLine(" ");
}
Console.ReadKey();
}
