diff --git a/history/005a1_letter_test/src/main/java/com/gitee/drinkjava2/frog/Application.java b/history/005a1_letter_test/src/main/java/com/gitee/drinkjava2/frog/Application.java
new file mode 100644
index 0000000..bc27bb7
--- /dev/null
+++ b/history/005a1_letter_test/src/main/java/com/gitee/drinkjava2/frog/Application.java
@@ -0,0 +1,122 @@
+package com.gitee.drinkjava2.frog;
+
+import java.awt.event.ActionEvent;
+import java.awt.event.ActionListener;
+import java.io.File;
+
+import javax.swing.ButtonGroup;
+import javax.swing.JButton;
+import javax.swing.JCheckBox;
+import javax.swing.JFrame;
+import javax.swing.JLabel;
+import javax.swing.JRadioButton;
+import javax.swing.JSlider;
+import javax.swing.event.ChangeEvent;
+import javax.swing.event.ChangeListener;
+
+import com.gitee.drinkjava2.frog.brain.BrainPicture;
+
+/**
+ * Application's main method start the program
+ * 
+ * @author Yong Zhu
+ * @since 1.0
+ */
+@SuppressWarnings("all")
+public class Application {
+
+    public static final String CLASSPATH;
+
+    static {
+        String classpath = new File("").getAbsolutePath();
+        int i = classpath.lastIndexOf("\\frog\\");
+        if (i > 0)
+            CLASSPATH = classpath.substring(0, i) + "\\frog\\";// windows
+        else
+            CLASSPATH = classpath + "/"; // UNIX
+    }
+
+    public static JFrame mainFrame = new JFrame();
+    public static Env env = new Env();
+    public static BrainPicture brainPic = new BrainPicture(Env.ENV_WIDTH + 5, 0, Env.FROG_BRAIN_XSIZE,
+            Env.FROG_BRAIN_DISP_WIDTH);
+    public static ActionListener pauseAction;
+    public static boolean selectFrog = true;
+
+    private static void checkIfShowBrainPicture(JButton button) {
+        if (Env.SHOW_FIRST_FROG_BRAIN) {
+            button.setText("Hide brain");
+            int y = Env.ENV_HEIGHT + 160;
+            if (Env.FROG_BRAIN_DISP_WIDTH + 41 > y)
+                y = Env.FROG_BRAIN_DISP_WIDTH + 41;
+            mainFrame.setSize(Env.ENV_WIDTH + Env.FROG_BRAIN_DISP_WIDTH + 25, y);
+            brainPic.requestFocus(); 
+        } else {
+            button.setText("Show brain");
+            mainFrame.setSize(Env.ENV_WIDTH + 20, Env.ENV_HEIGHT + 160);
+        }
+    }
+
+    public static void main(String[] args) {
+        mainFrame.setLayout(null);
+        mainFrame.setSize(Env.ENV_WIDTH + 20, Env.ENV_HEIGHT + 100); // 窗口大小
+        mainFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // 关闭时退出程序
+        mainFrame.add(env); // 添加虚拟环境Panel
+        mainFrame.add(brainPic); // 添加脑图Panel
+
+        JButton showBrainbutton = new JButton("Show brain");// 按钮，显示或隐藏脑图
+        int buttonWidth = 100;
+        int buttonHeight = 22;
+        int buttonXpos = Env.ENV_WIDTH / 2 - buttonWidth / 2;
+
+        showBrainbutton.setBounds(buttonXpos, Env.ENV_HEIGHT + 8, buttonWidth, buttonHeight);
+        ActionListener al = new ActionListener() {
+            @Override
+            public void actionPerformed(ActionEvent arg0) {//显示或隐藏脑图
+                Env.SHOW_FIRST_FROG_BRAIN = !Env.SHOW_FIRST_FROG_BRAIN;
+                checkIfShowBrainPicture(showBrainbutton);
+            }
+        };
+        checkIfShowBrainPicture(showBrainbutton);
+        showBrainbutton.addActionListener(al);
+        mainFrame.add(showBrainbutton);
+
+        JButton stopButton = new JButton("Pause");// 暂停或继续按钮
+        stopButton.setBounds(buttonXpos, Env.ENV_HEIGHT + 35, buttonWidth, buttonHeight);
+        pauseAction = new ActionListener() {
+            @Override
+            public void actionPerformed(ActionEvent arg0) {
+                Env.pause = !Env.pause;
+                if (Env.pause) {
+                    stopButton.setText("Resume");
+                } else {
+                    stopButton.setText("Pause");
+                    brainPic.requestFocus();
+                }
+            }
+        };
+        stopButton.addActionListener(pauseAction);
+        mainFrame.add(stopButton);
+
+        // 速度条
+        final JSlider speedSlider = new JSlider(1, 10, (int) Math.round(Math.sqrt(Env.SHOW_SPEED)));
+        speedSlider.setBounds(buttonXpos - 50, stopButton.getY() + 25, buttonWidth + 100, buttonHeight);
+        ChangeListener slideAction = new ChangeListener() {
+            @Override
+            public void stateChanged(ChangeEvent e) {
+                Env.SHOW_SPEED = speedSlider.getValue() * speedSlider.getValue() * speedSlider.getValue();
+                brainPic.requestFocus();
+            }
+        };
+        speedSlider.addChangeListener(slideAction);
+        mainFrame.add(speedSlider);
+        final JLabel label = new JLabel("Speed:");
+        label.setBounds(buttonXpos - 90, stopButton.getY() + 23, 100, buttonHeight);
+        mainFrame.add(label);
+ 
+   
+        mainFrame.setVisible(true);
+        env.run();
+    }
+
+}