diff --git a/history/003a_legs/src/main/java/com/github/drinkjava2/frog/egg/Egg.java b/history/003a_legs/src/main/java/com/github/drinkjava2/frog/egg/Egg.java
new file mode 100644
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+++ b/history/003a_legs/src/main/java/com/github/drinkjava2/frog/egg/Egg.java
@@ -0,0 +1,133 @@
+/*
+ * Copyright 2018 the original author or authors. 
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by
+ * applicable law or agreed to in writing, software distributed under the
+ * License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS
+ * OF ANY KIND, either express or implied. See the License for the specific
+ * language governing permissions and limitations under the License.
+ */
+package com.github.drinkjava2.frog.egg;
+
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.List;
+
+import com.github.drinkjava2.frog.Frog;
+import com.github.drinkjava2.frog.brain.Organ;
+import com.github.drinkjava2.frog.brain.group.Group;
+import com.github.drinkjava2.frog.brain.organ.Active;
+import com.github.drinkjava2.frog.brain.organ.BFootDrop;
+import com.github.drinkjava2.frog.brain.organ.BFootFeelDown;
+import com.github.drinkjava2.frog.brain.organ.BFootFeelUp;
+import com.github.drinkjava2.frog.brain.organ.BFootMoveLeft;
+import com.github.drinkjava2.frog.brain.organ.BFootMoveRight;
+import com.github.drinkjava2.frog.brain.organ.BFootRaise;
+import com.github.drinkjava2.frog.brain.organ.Chance;
+import com.github.drinkjava2.frog.brain.organ.Eat;
+import com.github.drinkjava2.frog.brain.organ.Eye;
+import com.github.drinkjava2.frog.brain.organ.FootPosFeel;
+import com.github.drinkjava2.frog.brain.organ.Happy;
+import com.github.drinkjava2.frog.brain.organ.Hungry;
+import com.github.drinkjava2.frog.brain.organ.LogicAnd;
+import com.github.drinkjava2.frog.brain.organ.LogicNot;
+import com.github.drinkjava2.frog.brain.organ.NewEye;
+import com.github.drinkjava2.frog.brain.organ.Pain;
+import com.github.drinkjava2.frog.brain.organ.RFootDrop;
+import com.github.drinkjava2.frog.brain.organ.RFootFeelDown;
+import com.github.drinkjava2.frog.brain.organ.RFootFeelUp;
+import com.github.drinkjava2.frog.brain.organ.RFootMoveDown;
+import com.github.drinkjava2.frog.brain.organ.RFootMoveUp;
+import com.github.drinkjava2.frog.brain.organ.RFootRaise;
+import com.github.drinkjava2.frog.util.RandomUtils;
+
+/**
+ * Egg is the static structure description of frog, can save as text file, to
+ * build a frog, first need build a egg.<br/>
+ * 
+ * 蛋存在的目的是为了以最小的字节数串行化存储Frog,它是Frog的生成算法描述，而不是Frog本身，这样一来Frog就不能"永生"了，因为每一个egg都不等同于
+ * 它的母体， 而且每一次测试，大部分条件反射的建立都必须从头开始训练，类似于人类，无论人类社会有多聪明， 婴儿始终是一张白纸，需要花大量的时间从头学习。
+ * 
+ * @author Yong Zhu
+ * @since 1.0
+ */
+public class Egg implements Serializable {
+	// 为了缩短时间，这个程序随机生成的联结将只落在固定的器官上而不是漫天撒网(见4.12提交)，这是程序的优化，实现的逻辑和随机漫天撒网定是相同的。
+	// 但是这个优化带来的问题是这是一个硬编码逻辑，不利于器官的优胜劣汰， 而且下面这个 FIXED_ORGAN_QTY必须每次手工设定，以后需要重构这块的代码
+	public static int FIXED_ORGAN_QTY = 11;
+
+	private static final long serialVersionUID = 1L;
+
+	public List<Organ> organs = new ArrayList<>();
+
+	public List<Group> groups = new ArrayList<>();
+
+	public Egg() {// 无中生有，创建一个蛋，先有蛋，后有蛙
+		organs.add(new Happy().setXYRN(600, 900, 60, "Happy")); // Happy必须第0个加入
+		organs.add(new Eye().setXYRN(100, 200, 100, "Eye"));// Eye必须第1个加入
+		organs.add(new NewEye().setXYRN(100, 900, 100, "NewEye"));// NewEye必须第2个加入
+
+		organs.add(new Hungry().setXYRN(300, 100, 60, "Hungry"));
+		organs.add(new Pain().setXYRN(800, 900, 60, "Pain")); // 痛苦在靠近边界时触发
+		organs.add(new Active().setXYRN(500, 100, 60, "Active")); // 永远激活
+		organs.add(new Chance().setXYRN(650, 100, 60, "Chance")); // 永远激活
+
+		organs.add(new BFootMoveLeft().setXYRN(150, 450, 30, "MoveLeft"));// 底脚向左移运动细胞
+		organs.add(new BFootMoveRight().setXYRN(300, 450, 30, "MoveRight"));// 底脚向右移运动细胞
+		organs.add(new BFootRaise().setXYRN(150, 520, 30, "Raise"));// 底脚抬起输出细胞
+		organs.add(new BFootDrop().setXYRN(300, 520, 30, "Drop"));// 底脚降下输出细胞
+		organs.add(new BFootFeelUp().setXYRN(150, 600, 30, "FeelUp"));// 底脚抬起感受细胞
+		organs.add(new BFootFeelDown().setXYRN(300, 600, 30, "FeelDown"));// 底脚降下感受细胞
+		for (int i = 0; i <= 10; i++)
+			organs.add(new FootPosFeel().setXYRN(FootPosFeel.BFOOTPOSSTART_X + i * 30, 650, 10, "")); // 底脚位置感受细胞
+
+		organs.add(new RFootMoveUp().setXYRN(650, 450, 30, "MoveUp"));// 底脚向左移运动细胞
+		organs.add(new RFootMoveDown().setXYRN(800, 450, 30, "MoveDown"));// 底脚向右移运动细胞
+		organs.add(new RFootRaise().setXYRN(650, 520, 30, "Raise"));// 底脚抬起输出细胞
+		organs.add(new RFootDrop().setXYRN(800, 520, 30, "Drop"));// 底脚降下输出细胞
+		organs.add(new RFootFeelUp().setXYRN(650, 600, 30, "FeelUp"));// 底脚抬起感受细胞
+		organs.add(new RFootFeelDown().setXYRN(800, 600, 30, "FeelDown"));// 底脚降下感受细胞
+		for (int i = 0; i <= 10; i++)
+			organs.add(new FootPosFeel().setXYRN(FootPosFeel.RFOOTPOSSTART_X + i * 30, 650, 10, "")); // 底脚位置感受细胞
+
+		//for (int i = 0; i < 5; i++) {
+		//	organs.add(new LogicAnd().setXYRN(100+i*30, 10, 5, "")); // 逻辑与器官，经测试没用上，暂排除
+		//	organs.add(new LogicNot().setXYRN(100+i*30, 50, 5, "")); // 逻辑非器官，经测试没用上，暂排除
+		//} 
+		
+		// 以上器官，就是FIXED_ORGAN_QTY值
+		FIXED_ORGAN_QTY = organs.size();
+		organs.add(new Eat().setXYRN(0, 0, 0, "Eat")); // EAT不是感觉或输出器官，没有位置和大小
+		 
+
+	}
+
+	/** Create egg from frog */
+	public Egg(Frog frog) { // 青蛙下蛋，每个青蛙的器官会创建自已的副本或变异，可以是0或多个
+		for (Organ organ : frog.organs)
+			for (Organ newOrgan : organ.vary())
+				organs.add(newOrgan);
+	}
+
+	/**
+	 * Create a egg by join 2 eggs, x+y=zygote 模拟X、Y 染色体合并，两个蛋生成一个新的蛋， X从Y里借一个器官,
+	 * 不用担心器官会越来越多，因为通过用进废退原则来筛选,没用到的器官会在几代之后被自然淘汰掉
+	 * 器官不是越多越好，因为器官需要消耗能量，器官数量多了，在生存竞争中也是劣势
+	 * 
+	 */
+	public Egg(Egg x, Egg y) {
+		// x里原来的organ
+		for (Organ organ : x.organs)
+			organs.add(organ);
+
+		// 从y里借一个organ
+		int yOrganSize = y.organs.size();
+		if (yOrganSize > 0) {
+			Organ o = y.organs.get(RandomUtils.nextInt(yOrganSize));
+			if (o.allowBorrow())
+				organs.add(o);
+		}
+	}
+
+}