diff --git a/history/005b_letter_test/src/main/java/com/gitee/drinkjava2/frog/brain/organ/Ear.java b/history/005b_letter_test/src/main/java/com/gitee/drinkjava2/frog/brain/organ/Ear.java
new file mode 100644
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--- /dev/null
+++ b/history/005b_letter_test/src/main/java/com/gitee/drinkjava2/frog/brain/organ/Ear.java
@@ -0,0 +1,76 @@
+/*
+ * 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.gitee.drinkjava2.frog.brain.organ;
+
+import com.gitee.drinkjava2.frog.Env;
+import com.gitee.drinkjava2.frog.Frog;
+import com.gitee.drinkjava2.frog.brain.Cuboid;
+import com.gitee.drinkjava2.frog.brain.Organ;
+import com.gitee.drinkjava2.frog.util.ColorUtils;
+
+/**
+ * Ear can accept sound input
+ * 
+ * 耳朵的信号输入区能输入多少个信号取决于它的长度，它的每个输入点都与视觉视号正交
+ * 
+ * 耳朵的输入区在2021年6月后改只取 0,2,4,6,8处的细胞作为输入点以获取更清晰反向激活信号，这样总共就是5个有效输入点
+ * 
+ * 耳朵目前只有一个, 以后可以在侧面再开一个耳朵，就可以达到5x5=25个声音的输入
+ * 
+ * 为简单化，耳朵的识别区和输入区重叠，而不是象人脑一样有单独的虚拟声音，将来在信号强度上作区分，直接听到的信号强度大，反向激活后得到的信号弱
+ * 
+ * @author Yong Zhu
+ * @since 2.0.2
+ */
+@SuppressWarnings("all")
+public class Ear extends Organ {// 耳朵位于脑的顶上，也是长方体
+	private static final long serialVersionUID = 1L;
+
+	public Ear() {
+		this.shape = new Cuboid(11, 5, 20, 10, 10, 1);// 手工固定耳区的大小
+		this.type = Organ.EAR;
+		this.organName = "Ear";
+		this.allowVary = false;// 不允许变异
+		this.allowBorrow = false;// 不允许借出
+		this.color = ColorUtils.BLUE;
+	}
+
+    public void hearSound(Frog f, int code) {//code取0~4，分听代表5个听力细胞的位置
+        Cuboid c = (Cuboid) this.shape;
+        int x = code / 5;
+        int y = code % 5;
+        f.getOrCreateCell(c.x + x * 2, c.y + y * 2, c.z).hasInput = true; //听力细胞间隔一个分布
+    }
+
+	public int readcode(Frog f) {//找出收取光子数最多的点
+		int temp = -10000;
+		int code = -1;
+		Cuboid c = (Cuboid) this.shape;
+		System.out.print("Ear received photons qty: ");
+		for (int x = 0; x <=4; x++)  
+            for (int y = 0; y <= 4; y++) {
+                int sum = f.getOrCreateCell(c.x+x*2, c.y + y * 2, c.z).photonSum;
+                System.out.print(sum + ",");
+                if (sum > temp) {
+                    code = x*5 + y;
+                    temp = sum;
+                }
+            }
+		System.out.println();
+		return code;
+	}
+
+	/** 给这个耳朵听到一个字母，激活它的听觉输入区, 注意听觉输入区并不等于听觉成像区 */
+	public void hearNothing(Frog f) {
+		f.setCuboidVales((Cuboid) shape, false);
+	}
+
+}