using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        int[,] figureL = {{0, 1, 0},

                 {0, 1, 0},

                  {0, 1, 1}};

        Console.WriteLine(string.Join("\n",figureL.FindIndices(x => x == 1)));

    }

}

​

public static class Extensions

{

    public static IEnumerable<(int,int)> FindIndices<T>(this T[,] source, Func<T,bool> predicate)

    {

        for (var i = 0; i < source.GetLength(0); i++)

        {

            for (var j = 0; j < source.GetLength(1); j++)

            {

                if(predicate.Invoke(source[i,j]))

                {

                     yield return (i,j);

                }

            }

        }

    }

}