diff --git a/L3/K2/Duomenys.txt b/L3/K2/Duomenys.txt
new file mode 100644
index 0000000..670d33c
--- /dev/null
+++ b/L3/K2/Duomenys.txt
@@ -0,0 +1,5 @@
+Toshiba;123Bąčę;1200.01
+Foobar;AAA;1300.01
+Foobar;AAB;1300.01
+Foobar;BBB;1350.01
+Baz BAAAZ;The FOO - BAZ;1700.12345
\ No newline at end of file
diff --git a/L3/K2/K2.csproj b/L3/K2/K2.csproj
new file mode 100644
index 0000000..ab828a7
--- /dev/null
+++ b/L3/K2/K2.csproj
@@ -0,0 +1,14 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>netcoreapp3.1</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <None Update="Duomenys.txt">
+      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+    </None>
+  </ItemGroup>
+
+</Project>
diff --git a/L3/K2/Program.cs b/L3/K2/Program.cs
new file mode 100644
index 0000000..4061616
--- /dev/null
+++ b/L3/K2/Program.cs
@@ -0,0 +1,372 @@
+using System;
+using System.IO;
+
+namespace K2
+{
+    public interface IBetween<T>
+    {
+        /// <summary>
+        /// Indicates whether the value of the certain property of the current instance is in
+        /// [<paramref name="from"/>, <paramref name="to"/>] range including range marginal values.
+        /// <paramref name="from"/> should always precede <paramref name="to"/> in default sort order.
+        /// </summary>
+        /// <param name="from">The starting value of the range</param>
+        /// <param name="to">The ending value of the range</param>
+        /// <returns>true if the value of the current object property is in range; otherwise,
+        /// false.</returns>
+        bool MutuallyInclusiveBetween(T from, T to);
+
+        /// <summary>
+        /// Indicates whether the value of the certain property of the current instance is in
+        /// [<paramref name="from"/>, <paramref name="to"/>] range excluding range marginal values.
+        /// <paramref name="from"/> should always precede <paramref name="to"/> in default sort order.
+        /// </summary>
+        /// <param name="from">The starting value of the range</param>
+        /// <param name="to">The ending value of the range</param>
+        /// <returns>true if the value of the current object property is in range; otherwise,
+        /// false.</returns>
+        bool MutuallyExclusiveBetween(T from, T to);
+    }
+
+    /// <summary>
+    /// Provides generic container where the data are stored in the linked list.
+    /// </summary>
+    /// <typeparam name="T">The type of the data to be stored in the list. Data
+    /// class should implement some interfaces.</typeparam>
+    public class LinkList<T>
+        where T: IComparable<T>
+    {
+        class Node
+        {
+            public T Data { get; set; }
+            public Node Next { get; set; }
+            public Node(T data, Node next)
+            {
+                Data = data;
+                Next = next;
+            }
+        }
+
+        /// <summary>
+        /// All the time should point to the first element of the list.
+        /// </summary>
+        private Node begin;
+
+        /// <summary>
+        /// All the time should point to the last element of the list.
+        /// </summary>
+        private Node end;
+
+        /// <summary>
+        /// Shouldn't be used in any other methods except Begin(), Next(), Exist() and Get().
+        /// </summary>
+        private Node current;
+
+        /// <summary>
+        /// Initializes a new instance of the LinkList class with empty list.
+        /// </summary>
+        public LinkList()
+        {
+            begin = current = end = null;
+        }
+
+        /// <summary>
+        /// One of four interface methods devoted to loop through a list and get value stored in it.
+        /// Method should be used to move internal pointer to the first element of the list.
+        /// </summary>
+        public void Begin()
+        {
+            current = begin;
+        }
+        
+        /// <summary>
+        /// One of four interface methods devoted to loop through a list and get value stored in it.
+        /// Method should be used to move internal pointer to the next element of the list.
+        /// </summary>
+        public void Next()
+        {
+            current = current.Next;
+        }
+
+        /// <summary>
+        /// One of four interface methods devoted to loop through a list and get value stored in it.
+        /// Method should be used to check whether the internal pointer points to the element of the list.
+        /// </summary>
+        /// <returns>true, if the internal pointer points to some element of the list; otherwise,
+        /// false.</returns>
+        public bool Exist()
+        {
+            return current != null;
+        }
+
+        /// <summary>
+        /// One of four interface methods devoted to loop through a list and get value stored in it.
+        /// Method should be used to get the value stored in the node pointed by the internal pointer.
+        /// </summary>
+        /// <returns>the value of the element that is pointed by the internal pointer.</returns>
+        public T Get()
+        {
+            return current.Data;
+        }
+
+        /// <summary>
+        /// Method appends new node to the end of the list and saves in it <paramref name="data"/>
+        /// passed by the parameter.
+        /// </summary>
+        /// <param name="data">The data to be stored in the list.</param>
+        public void Add(T data)
+        {
+            var node = new Node(data, null);
+            if (begin == null)
+            {
+                begin = node;
+                end = node;
+            } else
+            {
+                end.Next = node;
+                end = node;
+            }
+        }
+
+        /// <summary>
+        /// Method sorts data in the list. The data object class should implement IComparable
+        /// interface though defining sort order.
+        /// </summary>
+        public void Sort()
+        {
+            for (Node nodeA = begin; nodeA != null; nodeA = nodeA.Next)
+            {
+                if (nodeA.Next == null) continue;
+
+                for (Node nodeB = nodeA.Next; nodeB != null; nodeB = nodeB.Next)
+                {
+                    if (nodeA.Data.CompareTo(nodeB.Data) < 0)
+                    {
+                        T tmp = nodeA.Data;
+                        nodeA.Data = nodeB.Data;
+                        nodeB.Data = tmp;
+                    }
+                }
+            }
+        }
+    }
+
+    /// <summary>
+    /// Provides properties and interface implementations for the storing and manipulating of cars data.
+    /// </summary>
+    public class Car : IComparable<Car>, IBetween<double>, IBetween<string>
+    {
+        public string Manufacturer { get; set; }
+        public string Model { get; set; }
+        public double Price { get; set; }
+
+        public Car(string manufacturer, string model, double price)
+        {
+            Manufacturer = manufacturer;
+            Model = model;
+            Price = price;
+        }
+
+        /// <summary>
+        /// Compares the current instance with another object of the same type and returns an integer
+        /// that indicates whether the current instance precedes, follows, or occurs in the same
+        /// position in the sort order as the other object.
+        /// </summary>
+        /// <param name="other">An object to compare with this instance.</param>
+        /// <returns>A value that indicates the relative order of the objects being compared.The
+        /// return value has these meanings: -1 when this instance precedes other in the sort order;
+        /// 0 when this instance occurs in the same position in the sort order as other;
+        /// 1 when this instance follows other in the sort order.</returns>
+        public int CompareTo(Car other)
+        {
+            if (Price < other.Price)
+            {
+                return -1;
+            } else if (Price == other.Price)
+            {
+                return -Model.CompareTo(other.Model);
+            } else
+            {
+                return 1;
+            }
+        }
+
+        public bool MutuallyInclusiveBetween(double from, double to)
+        {
+            return from <= Price && Price <= to;
+        }
+
+        public bool MutuallyExclusiveBetween(double from, double to)
+        {
+            return from < Price && Price < to;
+        }
+
+        public bool MutuallyInclusiveBetween(string from, string to)
+        {
+            return Manufacturer.CompareTo(from) <= 0 && Manufacturer.CompareTo(to) >= 0;
+        }
+
+        public bool MutuallyExclusiveBetween(string from, string to)
+        {
+            return Manufacturer.CompareTo(from) < 0 && Manufacturer.CompareTo(to) > 0;
+        }
+    }
+
+    public static class InOut
+    {
+        /// <summary>
+        /// Creates the list containing data read from the text file.
+        /// </summary>
+        /// <param name="fileName">The name of the text file</param>
+        /// <returns>List with data from file</returns>
+        public static LinkList<Car> ReadFromFile(string fileName)
+        {
+            var cars = new LinkList<Car>();
+            foreach (var line in File.ReadAllLines(fileName))
+            {
+                string[] parts = line.Split(';');
+                string manufacturer = parts[0].Trim();
+                string model = parts[1].Trim();
+                double price = double.Parse(parts[2].Trim());
+                cars.Add(new Car(manufacturer, model, price));
+            }
+            return cars;
+        }
+
+        /// <summary>
+        /// Appends the table, built from data contained in the list and preceded by the header,
+        /// to the end of the text file.
+        /// </summary>
+        /// <param name="fileName">The name of the text file</param>
+        /// <param name="header">The header of the table</param>
+        /// <param name="list">The list from which the table to be formed</param>
+        public static void PrintToFile(string fileName, string header, LinkList<Car> list)
+        {
+            using (var writer = new StreamWriter(fileName, true))
+            {
+                writer.WriteLine(new string('-', 53));
+                writer.WriteLine("| {0, -49} |", header);
+                writer.WriteLine(new string('-', 53));
+
+                // Klausimas: Ar GRIEŽTAI negalima kurtis savo pagalbinių funkcijų?
+                //  Nes šitoje situacijoje žemiau labai praverstų tiesiog susikurti `IsEmpty` metodą.
+                //  Kartu prie to pačio, man labai nepatinka `Begin`, `Exist` ir `Next`, tai koks `IEnumerable`
+                // manau yra žymiai geresnis sprendimas, kad kaip sukti ciklą per listą.
+                list.Begin();
+                if (list.Exist())
+                {
+                    writer.WriteLine("| {0,-20} | {1,-15} | {2,8} |", "Gamintojas", "Modelis", "Kaina");
+                    writer.WriteLine(new string('-', 53));
+                    for (list.Begin(); list.Exist(); list.Next())
+                    {
+                        var car = list.Get();
+                        writer.WriteLine("| {0,-20} | {1,-15} | {2,8:f2} |", car.Manufacturer, car.Model, car.Price);
+                    }
+                } else
+                {
+                    writer.WriteLine("| {0, -49} |", "Nėra");
+                }
+                writer.WriteLine(new string('-', 53));
+                writer.WriteLine();
+            }
+        }
+    }
+
+    public static class Task
+    {
+        /// <summary>
+        /// The method finds the biggest price value in the given list.
+        /// </summary>
+        /// <param name="list">The data list to be searched.</param>
+        /// <returns>The biggest price value.</returns>
+        public static double MaxPrice(LinkList<Car> list)
+        {
+            double maxPrice = -1;
+            for (list.Begin(); list.Exist(); list.Next())
+            {
+                var car = list.Get();
+                maxPrice = Math.Max(maxPrice, car.Price);
+            }
+            return maxPrice;
+        }
+
+        /// <summary>
+        /// Filters data from the source list that meets filtering criteria and writes them
+        /// into the new list.
+        /// </summary>
+        /// <typeparam name="TData">The type of the data objects stored in the list</typeparam>
+        /// <typeparam name="TCriteria">The type of criteria</typeparam>
+        /// <param name="source">The source list from which the result would be created</param>
+        /// <param name="from">Lower bound of the interval</param>
+        /// <param name="to">Upper bound of the interval</param>
+        /// <returns>The list that contains filtered data</returns>
+        public static LinkList<TData> Filter<TData, TCriteria>(LinkList<TData> source, TCriteria from, TCriteria to)
+                where TData : IComparable<TData>, IBetween<TCriteria>
+        {
+            var filtered = new LinkList<TData>();
+            for (source.Begin(); source.Exist(); source.Next())
+            {
+                var item = source.Get();
+                if (item.MutuallyInclusiveBetween(from, to))
+                {
+                    filtered.Add(item);
+                }
+            }
+            return filtered;
+        }
+    }
+
+    class Program
+    {
+        // Klausimas: Ar reikia kurti testus `LinkList` klasei?
+        static void Main()
+        {
+            string inputFilename = "Duomenys.txt";
+            string outputFilename = "Rezultatai.txt";
+            File.Delete(outputFilename);
+
+            Console.Write("Įveskite pirmą gamintoją: ");
+            string manufacturer1 = Console.ReadLine();
+            Console.Write("Įveskite antrą gamintoją: ");
+            string manufacturer2 = Console.ReadLine();
+
+            var cars1 = InOut.ReadFromFile(inputFilename);
+            InOut.PrintToFile(outputFilename, "Pradinės mašinos", cars1);
+
+            var cars2 = Task.Filter(cars1, manufacturer1, manufacturer1);
+            var cars3 = Task.Filter(cars1, manufacturer2, manufacturer2);
+            InOut.PrintToFile(outputFilename, string.Format("Mašinos pagal gamintoją '{0}'", manufacturer1), cars2);
+            InOut.PrintToFile(outputFilename, string.Format("Mašinos pagal gamintoją '{0}'", manufacturer2), cars3);
+
+            var maxPrice = Task.MaxPrice(cars1);
+            var cars4 = Task.Filter(cars2, maxPrice * 0.75, maxPrice);
+            var cars5 = Task.Filter(cars3, maxPrice * 0.75, maxPrice);
+            cars4.Sort();
+            cars5.Sort();
+            InOut.PrintToFile(outputFilename, string.Format("Brangios mašinos pagal gamintoją '{0}'", manufacturer1), cars4);
+            InOut.PrintToFile(outputFilename, string.Format("Brangios mašinos pagal gamintoją '{0}'", manufacturer2), cars5);
+
+            // Klausimas: Ar galima įdėti išdemą į failą maine?
+            //  Taip, žinau per LD darbus negalima tai daryti. Bet K2 apraše
+            // parašyta, kad negalima pridėti naujų metodų ar keisti egzistuojančių
+            // kamienus.
+            //  Bet reikalaujama išvesti surastą didžiausią kainą į failo galą
+            // su paaiškinamu tekstu.
+            // Paradoksas ¯\_(ツ)_/¯
+            using (var writer = new StreamWriter(outputFilename, true))
+            {
+                writer.WriteLine("Didžiausia mašinos kaina: {0:f2}", maxPrice);
+            }
+
+            // Klausimas: KAS SUGALVOJO ŠITĄ UŽDUOTĮ?!?!?!
+            //  Niekada nebuvau matęs, kad kas būtų naudojąs interface užklojimiui vieno
+            // lauko palyginimiui pagal tipą. IR DAR tą inteface reikia panaudoti 2 kartus ant `Car`
+            // klasės, kad būtų galima patikrinti skirtingus laukus?!
+            //  Čia atrodo, kad kažkas bandė išsisukinėti, kad nereikėtų kurti 2 `Task.Filter`
+            // ir galų gale gavosi, kad reikia aplamai turėti daugiau kodo kad pasiekti tą patį
+            // rezultatą. Ir dar ant viršaus, jeigu to nepakako `MutuallyExclusiveBetween` metodai
+            // lieka nepanaudoti.
+            // Ką galiu pasakyti tai, kad man labai nepatiko šita užduotis.
+        }
+    }
+}
diff --git a/L3/L3.sln b/L3/L3.sln
index 48a6674..8ac655c 100644
--- a/L3/L3.sln
+++ b/L3/L3.sln
@@ -5,7 +5,9 @@ VisualStudioVersion = 17.1.32210.238
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "LD_24", "LD_24\LD_24.csproj", "{AE159626-A105-440C-B997-F377C5F8F280}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "LD_24Tests", "LD_24Tests\LD_24Tests.csproj", "{39E0FA27-E323-45EE-BA1B-5DDFE00A7C03}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "LD_24Tests", "LD_24Tests\LD_24Tests.csproj", "{39E0FA27-E323-45EE-BA1B-5DDFE00A7C03}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "K2", "K2\K2.csproj", "{2C869FE9-7C18-4EA6-BE85-B4B10A557F25}"
 EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
@@ -21,6 +23,10 @@ Global
 		{39E0FA27-E323-45EE-BA1B-5DDFE00A7C03}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{39E0FA27-E323-45EE-BA1B-5DDFE00A7C03}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{39E0FA27-E323-45EE-BA1B-5DDFE00A7C03}.Release|Any CPU.Build.0 = Release|Any CPU
+		{2C869FE9-7C18-4EA6-BE85-B4B10A557F25}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{2C869FE9-7C18-4EA6-BE85-B4B10A557F25}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{2C869FE9-7C18-4EA6-BE85-B4B10A557F25}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{2C869FE9-7C18-4EA6-BE85-B4B10A557F25}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE