(adsbygoogle = window.adsbygoogle || []).push({}); Vector2

    using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;



namespace Math2D

{

    public class Vector2D : ICloneable

    {

        public Vector2D(double x, double y)

        {

            vectors.Add(0, x);

            vectors.Add(1, y);

        }



        private Dictionary<int, double> vectors = new Dictionary<int, double>(); //Store the 2 coords.



        public object Clone()

        {

            return new Vector2D(this[0], this[1]);

        }



        public double this[int c] //Indexing

        {

            get

            {

                if (c == 0 || c == 1)

                    return vectors[c];

                else

                    throw new IndexOutOfRangeException();

            }



            set

            {

                if (c == 0 || c == 1)

                    vectors[c] = value;

                else

                    throw new IndexOutOfRangeException();

            }

        }

    }

}

Line:

    using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;



namespace Math3D

{

    public class Line : ICloneable

    {

        private Vector2D pointOne;

        private Vector2D pointTwo;



        public double X1

        {

            get { return pointOne[0]; }

            set { pointOne[0] = value; }

        }



        public double X2

        {

            get { return pointTwo[0]; }

            set { pointTwo[0] = value; }

        }



        public double Y1

        {

            get { return pointOne[1]; }

            set { pointOne[1] = value; }

        }



        public double Y2

        {

            get { return pointTwo[1]; }

            set { pointTwo[1] = value; }

        }



        public double Length

        {

            get

            {

                double xl = Math.Pow(pointTwo[0] - pointOne[0], 2);

                double yl = Math.Pow(pointTwo[1] - pointOne[1], 2)  ;

                double results = xl + yl;

                return Math.Sqrt(results);

            }

        }



        public Line(Vector2D p1, Vector2D p2)

        {

            pointOne = p1;

            pointTwo = p2;

        }



        public static bool IsPerpendicular(Line a, Line b)

        {

            return (a.Y2 - a.Y1) / (a.X2 - a.X1) 

                ==

                -1 * (1 / ((b.Y2 - b.Y1) / (b.X2 - b.X1)));

        }



        public static bool IsParallel(Line a, Line b)

        {

            return (a.Y2 - a.Y1) / (a.X2 - a.X2)

                ==

                (b.Y2 - b.Y1) / (b.X2 - b.X1);

        }



        public object Clone()

        {

            Line line = new Line(pointOne, pointTwo);

            return (object)line;

        }

    }

}

Square:

    using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;



namespace Math3D

{

    public class Square

    {

        private Vector2D p1;

        private Vector2D p2;

        private Vector2D p3;

        private Vector2D p4;

        private List<Line> lines = new List<Line>();



        public Line this[int index]

        {

            get 

            {

                if (index <= 3 && index >= 0)

                    return lines[index];

                else

                    throw new IndexOutOfRangeException();

            }

        }



        public Square(Vector2D p1, Vector2D p2, Vector2D p3, Vector2D p4)

        {

            Line[] Lines = new Line[]

            {

                new Line(p1,p2),

                new Line(p2,p3),

                new Line(p3,p4),

                new Line(p4,p1)

            };



            for (int x = 0; x < 2; x++)

            {

                lines.Add(Lines[x]);

                lines.Add(Lines[x + 2]);



                if (!Line.IsParallel(Lines[x], Lines[x + 2]))

                    throw new NotASquareException("The lines do not form 90 degree angles.");

            }



            if (Lines[0].Length != Lines[1].Length || Lines[0].Length != Lines[2].Length || Lines[0].Length != Lines[3].Length)

                throw new NotASquareException("The length of the lines are not equal.");

            if(Lines[1].Length != Lines[2].Length ||Lines[1].Length != Lines[3].Length)

                throw new NotASquareException("The length of the lines are not equal.");

            if(Lines[2].Length != Lines[3].Length)

                throw new NotASquareException("The length of the lines are not equal.");



            this.p1 = p1;

            this.p2 = p2;

            this.p3 = p3;

            this.p4 = p4;

        }

    }

}

NotASquareException:

    using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;



namespace Math3D

{

    public class NotASquareException : Exception

    {

        public NotASquareException() : base() { }

        public NotASquareException(string msg) : base(msg) { }

    }

}

Do with it what you want