using System;
using System.Drawing;
namespace WindowsApplication1
{
    class Ball
    {
        Graphics g;
        Point center;
        int size, curSize;
        bool IsToLeft, IsToTop, IsExpanding;
        int speed;
        Color clr;

        static Random r = new Random();
        public static Rectangle rct;
        int Angle;


        public Ball(Graphics g)
        {
            this.g = g;
            this.center = new Point(r.Next() % rct.Width, r.Next() % rct.Height);

            this.clr = Color.FromArgb(255, r.Next() % 255, r.Next() % 255, r.Next() % 255);
            this.size = r.Next() % 100 + 10;
            this.curSize = r.Next() % this.size + 1;
            IsToLeft = (r.Next() % 2 == 0);
            IsToTop = (r.Next() % 2 == 0);
            IsExpanding = (r.Next() % 2 == 0);
            Angle = r.Next() % 360;            
            speed = r.Next()%(size/5)+2;
            
        }
       void Draw(Color c)
        {

           

            Pen pn = new Pen(c);
            pn.Width = 5;
            g.DrawEllipse(pn, center.X - curSize / 2, center.Y - curSize / 2, curSize, curSize);

            Point pt = new Point();
           double nCos= Math.Cos(Angle * Math.PI / 180);
           double nSin = Math.Sin(Angle * Math.PI / 180);


           pt.X = center.X + (int)(curSize *  nCos/2);
           pt.Y = center.Y + (int) (curSize* nSin/2);
           g.DrawLine(pn, pt.X, pt.Y, center.X, center.Y);



        }

        public void Move()
        {

            Draw(Color.Black);
            CheckHit();
            if (IsToLeft)
                center.X -= speed;
            else
                center.X += speed;
            
            if (IsToTop)
                center.Y -= speed;
            else
                center.Y += speed;

            if (IsExpanding)
                curSize+=size/10;
            else
                curSize-=size/10;

            Angle+=15;

            Draw(clr);
        }



        public void CheckHit()
        {
            if (rct.Left >= center.X - curSize / 2)
                IsToLeft = false;

            if (rct.Top >= center.Y - curSize / 2)
                IsToTop = false;

            if (rct.Right <= center.X + curSize )
                IsToLeft = true;
            if (rct.Bottom <= center.Y + curSize )
                IsToTop = true;

            if (curSize <= size/4)
                IsExpanding = true;
            if (curSize >= size)
                IsExpanding = false;
        }
    }
}

    public partial class Form1 : Form
    {
        Ball[] ar;
        public Form1()
        {
            InitializeComponent();
        }


        private void Form1_Load(object sender, EventArgs e)
        {
            ar = new Ball[10];
            Ball.rct = new Rectangle(0, 0, Width, Height);

            Random r = new Random();
            
            Graphics g = this.CreateGraphics();
            for (int i = 0; i < ar.Length;i++ )
            {
                ar[i] = new Ball(g);
            }
        }

       

        private void timer1_Tick(object sender, EventArgs e)
        {
        
            foreach (Ball b in ar)
            {
                b.Move();
            }
        }
    }