diff --git a/history/004_seasaw/src/main/java/com/github/drinkjava2/frog/brain/BrainPicture.java b/history/004_seasaw/src/main/java/com/github/drinkjava2/frog/brain/BrainPicture.java
new file mode 100644
index 0000000..44de23f
--- /dev/null
+++ b/history/004_seasaw/src/main/java/com/github/drinkjava2/frog/brain/BrainPicture.java
@@ -0,0 +1,128 @@
+package com.github.drinkjava2.frog.brain;
+
+import static java.awt.Color.BLUE;
+import static java.awt.Color.CYAN;
+import static java.awt.Color.GREEN;
+import static java.awt.Color.MAGENTA;
+import static java.awt.Color.ORANGE;
+import static java.awt.Color.RED;
+import static java.awt.Color.YELLOW;
+
+import java.awt.Color;
+import java.awt.Graphics;
+
+import javax.swing.JPanel;
+
+import com.github.drinkjava2.frog.Application;
+import com.github.drinkjava2.frog.Frog;
+
+/**
+ * BrainPicture show first frog's brain structure, for debug purpose only
+ * 
+ * @author Yong Zhu
+ * @since 1.0
+ */
+@SuppressWarnings("serial")
+public class BrainPicture extends JPanel {
+	private float brainWidth; // real brain width
+	private int brainDispWidth; // screen display width
+	private Color color = Color.BLACK;
+
+	public void setColor(Color c) {
+		color = c;
+	}
+
+	public BrainPicture(int x, int y, float brainWidth, int brainDispWidth) {
+		super();
+		this.setLayout(null);// 空布局
+		this.brainDispWidth = brainDispWidth;
+		this.brainWidth = brainWidth;
+		this.setBounds(x, y, brainDispWidth + 1, brainDispWidth + 1);
+	}
+
+	public void drawZone( Zone z) {Graphics g = this.getGraphics();
+	g.setColor(color);
+		float rate = brainDispWidth / brainWidth;
+		int x = Math.round(z.x * rate);
+		int y = Math.round(z.y * rate);
+		int radius = Math.round(z.r * rate);
+		g.drawRect(x - radius, y - radius, radius * 2, radius * 2);
+	}
+
+	public void drawCircle( Zone z) {Graphics g = this.getGraphics();
+	g.setColor(color);
+		float rate = brainDispWidth / brainWidth;
+		int x = Math.round(z.x * rate);
+		int y = Math.round(z.y * rate);
+		g.drawArc(x - 5, y - 5, 10, 10, 0, 360);
+	}
+
+	public void fillZone( Zone z) {Graphics g = this.getGraphics();
+	g.setColor(color);
+		float rate = brainDispWidth / brainWidth;
+		int x = Math.round(z.x * rate);
+		int y = Math.round(z.y * rate);
+		int radius = Math.round(z.r * rate);
+		g.fillRect(x - radius, y - radius, radius * 2, radius * 2);
+	}
+
+	public void drawLine(Zone z1, Zone z2) {
+		Graphics g = this.getGraphics();
+		g.setColor(color);
+		float rate = brainDispWidth / brainWidth;
+		int x1 = Math.round(z1.x * rate);
+		int y1 = Math.round(z1.y * rate);
+		int x2 = Math.round(z2.x * rate);
+		int y2 = Math.round(z2.y * rate);
+		g.drawLine(x1, y1, x2, y2);
+	}
+
+	public void drawText( Zone z, String text) {Graphics g = this.getGraphics();
+	g.setColor(color);
+		float rate = brainDispWidth / brainWidth;
+		int x = Math.round(z.x * rate);
+		int y = Math.round(z.y * rate);
+		g.drawString(text, x - text.length() * 3 - 2, y);
+	}
+
+	private static final Color[] rainbow = new Color[] { RED, ORANGE, YELLOW, GREEN, CYAN, BLUE, MAGENTA };
+	private static int nextColor = 0;
+
+	public static Color nextRainbowColor() {
+		if (nextColor == rainbow.length)
+			nextColor = 0;
+		return rainbow[nextColor++];
+	}
+
+	public static Color color(float i) {
+		if (i == 0)
+			return Color.black;
+		if (i == 1)
+			return Color.RED;
+		if (i <= 3)
+			return Color.ORANGE;
+		if (i <= 10)
+			return Color.YELLOW;
+		if (i <= 20)
+			return Color.GREEN;
+		if (i <= 50)
+			return Color.CYAN;
+		if (i <= 100)
+			return Color.BLUE;
+		return Color.MAGENTA;
+	}
+
+	public void drawBrainPicture(Frog frog) {
+		if (!Application.SHOW_FIRST_FROG_BRAIN)
+			return;
+		Graphics g = this.getGraphics();// border
+		g.setColor(Color.WHITE);
+		g.fillRect(0, 0, brainDispWidth, brainDispWidth);
+		g.setColor(Color.black);
+		g.drawRect(0, 0, brainDispWidth, brainDispWidth);
+
+		for (Organ organ : frog.organs)
+			organ.drawOnBrainPicture(frog, this); // each organ draw itself
+	}
+
+}