using System;

using System.Collections;

using System.Linq;

using System.Collections.Generic;

using System.Net;

using System.Net.Http;

using System.Threading.Tasks;

​

public class Program

{

    // Driver Code

    public static void Main()

    {

        var list = CreateList(4, 4);

        list.Dump();

        list.Take(2).SelectMany(o => o.Take(2)).Dump();

    }

    public static List<List<(int, int)>> CreateList(int rows, int columns)

    {

        var mat = new List<List<(int, int)>>();

        for (int i = 0; i < rows * columns; i++)

        {

            // Find row and column index

            int row = i / columns;

            int col = i % columns;

            var r = mat.ElementAtOrDefault(row);

            if (r == null)

            {

                mat.Add(r = new List<(int, int)>());

            }

            r.Add((row,col));

        }

        return mat;

    }

    public static List<List<Device>> CreateDevices(int rows, int columns)

    {

        var mat = new List<List<Device>>();

        var tenantUuids = Enumerable.Range(0, rows).Select(_ => Guid.NewGuid()).ToArray();

​

        for (int i = 0; i < rows * columns; i++)

        {

            // Find row and column index

            int row = i / columns;

            int col = i % columns;

            var r = mat.ElementAtOrDefault(row);

            if (r == null)

            {

                mat.Add(r = new List<Device>());

            }

            r.Add(new Device { TenantUuid = tenantUuids[row], DeviceUuid = Guid.NewGuid() });

        }

        return mat;

    }

}

​

public class Device

{

    public Guid TenantUuid { get; set; }

    public Guid DeviceUuid { get; set; }

}