namespace WindowsFormsApplication2
{
    public partial class Form1 : Form
    {
        Timer ticker = new Timer();

        List<ButtonPos> buttons = new List<ButtonPos>();

        struct ButtonPos
        {
            public Button button;
            public Vector2 Velocity;
            public int LifeTime;
        }
        struct Vector2
        {
            public float X;
            public float Y;
            public Vector2(float X, float Y)
            {
                this.X = X;
                this.Y = Y;
            }
        }

        Random rnd = new Random();
        public Form1()
        {
            InitializeComponent();
            ticker.Tick += ticker_Tick;
            ticker.Interval = 15;
            ticker.Start();
        }


        DateTime time = DateTime.Now;
        Vector2 Gravitation = new Vector2(0, 5.5f);
        float factor = 0.05f;
        void ticker_Tick(object sender, EventArgs e)
        {
            var diff = (DateTime.Now - time);
            var ntime = new TimeSpan(2000000);
            if (diff > ntime)
            {
                buttons.Add(new ButtonPos
                    {
                        button = new Button(),
                        Velocity = new Vector2(rnd.Next(-100, 100), -150 + rnd.Next(-100, 0)),
                        LifeTime = 200
                    });
                var newbutton = buttons[buttons.Count-1];

                newbutton.button.Parent = this;
                newbutton.button.Location = label1.Location;
                newbutton.button.Text = "+";
                newbutton.button.Show();
                newbutton.button.Enabled = true;
                time = DateTime.Now;
            }


            for (int i = 0; i < buttons.Count; i++ )
            {
                var btn = buttons[i];
                btn.button.Location = new Point((int)(btn.button.Location.X + btn.Velocity.X * factor), (int)(btn.button.Location.Y + btn.Velocity.Y * factor));

                if (btn.button.Location.Y > this.ClientSize.Height)
                    btn.Velocity = new Vector2(btn.Velocity.X, btn.Velocity.Y * -1);

                btn.Velocity = new Vector2(btn.Velocity.X + Gravitation.X, btn.Velocity.Y + Gravitation.Y);
                btn.LifeTime--;

                if (btn.LifeTime < 0)
                {
                    buttons.RemoveAt(i);
                    btn.button.Hide();
                }
                else
                    buttons[i] = btn;
            }
        }
    }
}