diff --git a/history/004_seasaw/src/main/java/com/github/drinkjava2/frog/util/RandomUtils.java b/history/004_seasaw/src/main/java/com/github/drinkjava2/frog/util/RandomUtils.java
new file mode 100644
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--- /dev/null
+++ b/history/004_seasaw/src/main/java/com/github/drinkjava2/frog/util/RandomUtils.java
@@ -0,0 +1,115 @@
+/* Copyright 2018-2020 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.util;
+
+import java.util.Random;
+
+import com.github.drinkjava2.frog.Frog;
+import com.github.drinkjava2.frog.brain.Zone;
+import com.github.drinkjava2.frog.egg.Egg;
+
+/**
+ * Random Utilities used in this project
+ * 
+ * @author Yong Zhu
+ * @since 1.0
+ */
+public class RandomUtils {
+	private static final Random rand = new Random();
+
+	public static int nextInt(int i) {
+		return rand.nextInt(i);
+	}
+
+	public static float nextFloat() {
+		return rand.nextFloat();
+	}
+
+	/** Return a random zone inside of a zone */
+	public static Zone randomZoneInZone(Zone z) { // 在一个区内随机取一个小小区
+		return new Zone(z.x - z.r + z.r * 2 * rand.nextFloat(), z.y - z.r + z.r * 2 * rand.nextFloat(),
+				z.r * rand.nextFloat() * .04f);
+	}
+
+	/** Return a random zone inside of frog's random organ */
+	public static Zone randomPosInAnyFrogOrgan(Frog f) {
+		if (f.organs == null || f.organs.size() == 0)
+			throw new IllegalArgumentException("Can not call randomPosInRandomOrgan method when frog has no organ");
+		return randomZoneInZone(f.organs.get(RandomUtils.nextInt(Egg.FIXED_ORGAN_QTY)));
+	}
+
+	/** Return a random zone inside of frog's random organ */
+	public static Zone randomPosMostInNewEye(Frog f) {
+		if (f.organs == null || f.organs.size() == 0)
+			throw new IllegalArgumentException("Can not call randomPosInRandomOrgan method when frog has no organ");
+		if (RandomUtils.percent(95))
+			return randomZoneInZone(f.organs.get(7));// 这是一个硬编码，大部分新联接建立在newEye中
+		return randomZoneInZone(f.organs.get(RandomUtils.nextInt(Egg.FIXED_ORGAN_QTY)));
+	}
+
+	public static boolean percent(float percent) {
+		return rand.nextFloat() * 100 < percent;
+	}
+
+	// /** vary a zone position, size a little bit */
+	// public static void varyZone(Zone z) {
+	// int i = rand.nextInt(100);
+	// if (i < 95) // 有95的机率不变异
+	// return;
+	// z.x = varyByRate(z.x, 0.01f);
+	// z.y = varyByRate(z.y, 0.01f);
+	// z.r = varyByRate(z.r, 0.03f);
+	// }
+
+	// public static float varyByRate(float f, float rate) { // 用指定的机率变异
+	// boolean bigger = rand.nextInt(2) > 0;
+	// if (bigger)
+	// f = f + f * rate * rand.nextFloat() + .001f;
+	// else
+	// f = f - f * rate * rand.nextFloat() - .001f;
+	// if (Float.isNaN(f))
+	// f = 0f;
+	// if (f > 1000000f)
+	// f = 1000000f;
+	// else if (f < -1000000f)
+	// f = -1000000f;
+	// return f;
+	// }
+
+	// public static float vary(float f) { // 大部分时候不变，有极小机会变异,有极极小机会大变异，有极极极小机会大大大变异
+	// int i = rand.nextInt(100);
+	// if (i < 50) // 有50的机率不变异
+	// return f;
+	// float rate = 0.2f; // 50%机率在0.2倍范围变异
+	// if (i > 80)
+	// rate = 1f; // 有20%的机率在1倍的范围变异
+	// if (i > 90)
+	// rate = 10f; // 有10%的机率在10倍的范围变异
+	// if (i > 95)
+	// rate = 100f; // 有5%的机率在100倍的范围变异
+	// if (i > 98)
+	// rate = 1000f; // 有1%的机率在1000倍的范围变异
+	//
+	// boolean bigger = rand.nextInt(2) > 0;
+	// if (bigger)
+	// f = f + f * rate * rand.nextFloat() + .001f;
+	// else
+	// f = f - f * rate * rand.nextFloat() - .001f;
+	// if (Float.isNaN(f))
+	// f = 0f;
+	// if (f > 1000000f)
+	// f = 1000000f;
+	// else if (f < -1000000f)
+	// f = -1000000f;
+	// return f;
+	// }
+
+}