1_A

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace _1_A
{
    public partial class Form1 : Form
    {
        Random rnd = new Random();
        //Green Ball
        private int ball1Size = 50;
        private int ball1PosX;
        private int ball1PosY;
        private int step1X;
        private int step1Y;
        //Red Ball
        private int ball2Size = 100;
        private int ball2PosX;
        private int ball2PosY;
        private int step2X;
        private int step2Y;


        public Form1()
        {
            InitializeComponent();

            //Green Ball random starting point and Stepping
            ball1PosX = rnd.Next(0, this.panel1.Width - ball1Size);
            ball1PosY = rnd.Next(0, this.panel1.Height - ball1Size);
            step1X = rnd.Next(1, 5);
            step1Y = rnd.Next(1, 5);
            //Red Ball random starting point and Stepping
            ball2PosX = rnd.Next(0, this.panel1.Width - ball2Size);
            ball2PosY = rnd.Next(0, this.panel1.Height - ball2Size);
            step2X = rnd.Next(-5, -1);
            step2Y = rnd.Next(-5, -1);
        }

        private void Button_Click(object sender, EventArgs e)
        {
            richTextBox1.Text = "Some Text HERE";
        }

        private void button1_Click(object sender, EventArgs e)
        {
            this.timer1.Enabled = true;
        }

        private void Paint_Circle(object sender, PaintEventArgs e)
        {
            e.Graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
            e.Graphics.Clear(this.BackColor);
            //Green Ball
            e.Graphics.FillEllipse(Brushes.Green, ball1PosX, ball1PosY, ball1Size, ball1Size);
            e.Graphics.DrawEllipse(Pens.Black, ball1PosX, ball1PosY, ball1Size, ball1Size);
            //Red Ball
            e.Graphics.FillEllipse(Brushes.Red, ball2PosX, ball2PosY, ball2Size, ball2Size);
            e.Graphics.DrawEllipse(Pens.Black, ball2PosX, ball2PosY, ball2Size, ball2Size);
        }

        private void MoveBall(object sender, EventArgs e)
        {
            //Green Ball Update position
            ball1PosX += step1X;
            if ( ball1PosX < 0 || ball1PosX + ball1Size > this.panel1.Width)
            {
                step1X = -step1X;
            }
            ball1PosY += step1Y;
            if (ball1PosY < 0 || ball1PosY + ball1Size > this.panel1.Height)
            {
                step1Y = -step1Y;
            }

            //Green Ball Update position
            ball2PosX += step2X;
            if (ball2PosX < 0 || ball2PosX + ball2Size > this.panel1.Width)
            {
                step2X = -step2X;
            }
            ball2PosY += step2Y;
            if (ball2PosY < 0 || ball2PosY + ball2Size > this.panel1.Height)
            {
                step2Y = -step2Y;
            }

            //Refresh Balls
            this.panel1.Refresh();
        }
    }
}