diff --git a/history/005a1_letter_test/src/main/java/com/gitee/drinkjava2/frog/brain/Shape.java b/history/005a1_letter_test/src/main/java/com/gitee/drinkjava2/frog/brain/Shape.java
new file mode 100644
index 0000000..6976c53
--- /dev/null
+++ b/history/005a1_letter_test/src/main/java/com/gitee/drinkjava2/frog/brain/Shape.java
@@ -0,0 +1,30 @@
+/*
+ * 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;
+
+import java.io.Serializable;
+
+import com.gitee.drinkjava2.frog.Frog;
+
+/**
+ * Shape represents a 3d zone in brain
+ * 
+ * Shape用来表示脑内器官的形状,一个器官只能有一个shape
+ * 
+ * @author Yong Zhu
+ * @since 2.0.2
+ */
+public interface Shape extends Serializable {
+	/* Draw self on brain picture */
+	public void drawOnBrainPicture(BrainPicture pic); // 把自己在脑图上画出来
+
+	public void createCellsRegOrgan(Frog f, int orgNo); // 在Shape所代表的脑区内找到或创建Cell对象，并将器官号orgNo登记在cell里
+}