diff --git a/documents/AboutInteliJ.md b/documents/AboutInteliJ_1.md
similarity index 65%
rename from documents/AboutInteliJ.md
rename to documents/AboutInteliJ_1.md
index 35cb6994d27369c48a6388ea0fc343d53a587965..edfa20d578c8ad33f82edcac3300a47b273ece65 100644
--- a/documents/AboutInteliJ.md
+++ b/documents/AboutInteliJ_1.md
@@ -6,7 +6,7 @@
 
 2. 프로젝트 생성 대화상자에서 'Kotlin/JVM' 선택하고 Next를 누른다.
 
-   이를 통해 kotlinc-jvm컴파일러를 사용해서 코틀린 코드를 JVM(Java Virtual Machine)에서 실행할 수 있는 바이트코드로 변환할 수 있다. 우리는 이 과정을 '컴파일'이라고 부른다.
+   이를 통해 kotlinc-jvm 컴파일러를 사용해서 <u>코틀린 코드</u>를 JVM(Java Virtual Machine)에서 실행할 수 있는 바이트코드로 변환할 수 있다. JVM은 변환된 <u>바이트 코드</u>를 콘솔에 출력한다. 우리는 이 과정을 <strong>컴파일</strong>이라고 부른다.
 
 ![NewProjectsBox](./captures/NewProjectsBox.png)
 
@@ -32,9 +32,9 @@
 
 
 
+<strong> 실행하고자 하는 코드를 작성  →  ctrl + enter</strong>
+
+![ExecutingKotlinREPL](./captures/ExecutingKotlinREPL.png)
 
 
-### 인텔리제이 기능 단축키
 
-* *ctrl + shift + f10*: 프로그램 실행 (Run '~~~.kt')
-* 
\ No newline at end of file
diff --git a/documents/AboutInteliJ_2.md b/documents/AboutInteliJ_2.md
new file mode 100644
index 0000000000000000000000000000000000000000..f6d3dbaf93fabf7878c966628f19c0a2ac7d120c
--- /dev/null
+++ b/documents/AboutInteliJ_2.md
@@ -0,0 +1,7 @@
+# 인텔리제이 사용법 (2)
+
+### 인텔리제이 기능 단축키
+
+- <u>*'main' 작성 + tab*</u>: fun main(){ } 자동 생성
+- *ctrl + shift + f10*: 프로그램 실행 (Run '~~~.kt')
+- 
\ No newline at end of file
diff --git a/documents/captures/ExecutingKotlinREPL.png b/documents/captures/ExecutingKotlinREPL.png
new file mode 100644
index 0000000000000000000000000000000000000000..66f7cdff32e7fc9c95ae1238c10028782f6e81e4
Binary files /dev/null and b/documents/captures/ExecutingKotlinREPL.png differ
diff --git a/practice/sandbox/.idea/workspace.xml b/practice/sandbox/.idea/workspace.xml
index f3637cc32f362d67603f5b42d30b718068f56328..6a1d7b0e6bed0e78e6b3f1d04392c265cbfb3fea 100644
--- a/practice/sandbox/.idea/workspace.xml
+++ b/practice/sandbox/.idea/workspace.xml
@@ -1,7 +1,12 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
   <component name="ChangeListManager">
-    <list default="true" id="ce152a44-3679-4b6f-b288-a2eb11b5ddac" name="Default Changelist" comment="" />
+    <list default="true" id="ce152a44-3679-4b6f-b288-a2eb11b5ddac" name="Default Changelist" comment="">
+      <change beforePath="$PROJECT_DIR$/../../documents/AboutInteliJ.md" beforeDir="false" />
+      <change beforePath="$PROJECT_DIR$/.idea/workspace.xml" beforeDir="false" afterPath="$PROJECT_DIR$/.idea/workspace.xml" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/out/production/sandbox/TypeIntroKt.class" beforeDir="false" afterPath="$PROJECT_DIR$/out/production/sandbox/TypeIntroKt.class" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/src/TypeIntro.kt" beforeDir="false" afterPath="$PROJECT_DIR$/src/TypeIntro.kt" afterDir="false" />
+    </list>
     <ignored path="$PROJECT_DIR$/out/" />
     <option name="EXCLUDED_CONVERTED_TO_IGNORED" value="true" />
     <option name="SHOW_DIALOG" value="false" />
@@ -10,16 +15,15 @@
     <option name="LAST_RESOLUTION" value="IGNORE" />
   </component>
   <component name="DefaultGradleProjectSettings">
-    <option name="testRunner" value="GRADLE" />
-    <option name="delegatedBuild" value="true" />
+    <option name="isMigrated" value="true" />
   </component>
   <component name="FileEditorManager">
-    <leaf>
+    <leaf SIDE_TABS_SIZE_LIMIT_KEY="300">
       <file pinned="false" current-in-tab="true">
         <entry file="file://$PROJECT_DIR$/src/TypeIntro.kt">
           <provider selected="true" editor-type-id="text-editor">
-            <state relative-caret-position="57">
-              <caret line="3" column="1" lean-forward="true" selection-start-line="3" selection-start-column="1" selection-end-line="3" selection-end-column="1" />
+            <state relative-caret-position="209">
+              <caret line="11" column="32" selection-start-line="11" selection-start-column="32" selection-end-line="11" selection-end-column="32" />
             </state>
           </provider>
         </entry>
@@ -34,6 +38,9 @@
       </list>
     </option>
   </component>
+  <component name="Git.Settings">
+    <option name="RECENT_GIT_ROOT_PATH" value="$PROJECT_DIR$/../.." />
+  </component>
   <component name="IdeDocumentHistory">
     <option name="CHANGED_PATHS">
       <list>
@@ -46,11 +53,14 @@
     <option name="width" value="980" />
     <option name="height" value="1040" />
   </component>
+  <component name="ProjectLevelVcsManager" settingsEditedManually="true" />
   <component name="ProjectView">
     <navigator proportions="" version="1">
       <foldersAlwaysOnTop value="true" />
     </navigator>
     <panes>
+      <pane id="Scope" />
+      <pane id="PackagesPane" />
       <pane id="ProjectPane">
         <subPane>
           <expand>
@@ -62,25 +72,14 @@
               <item name="sandbox" type="b2602c69:ProjectViewProjectNode" />
               <item name="External Libraries" type="cb654da1:ExternalLibrariesNode" />
             </path>
-            <path>
-              <item name="sandbox" type="b2602c69:ProjectViewProjectNode" />
-              <item name="External Libraries" type="cb654da1:ExternalLibrariesNode" />
-              <item name="&lt; 1.8 &gt;" type="70bed36:NamedLibraryElementNode" />
-            </path>
-            <path>
-              <item name="sandbox" type="b2602c69:ProjectViewProjectNode" />
-              <item name="External Libraries" type="cb654da1:ExternalLibrariesNode" />
-              <item name="KotlinJavaRuntime" type="70bed36:NamedLibraryElementNode" />
-            </path>
           </expand>
           <select />
         </subPane>
       </pane>
-      <pane id="PackagesPane" />
-      <pane id="Scope" />
     </panes>
   </component>
   <component name="PropertiesComponent">
+    <property name="SHARE_PROJECT_CONFIGURATION_FILES" value="true" />
     <property name="settings.editor.selected.configurable" value="configurable.group.appearance" />
   </component>
   <component name="RunDashboard">
@@ -128,49 +127,53 @@
     </task>
     <servers />
   </component>
+  <component name="TodoView">
+    <todo-panel id="selected-file">
+      <is-autoscroll-to-source value="true" />
+    </todo-panel>
+    <todo-panel id="all">
+      <are-packages-shown value="true" />
+      <is-autoscroll-to-source value="true" />
+    </todo-panel>
+  </component>
   <component name="ToolWindowManager">
     <frame x="-7" y="-7" width="1550" height="838" extended-state="6" />
+    <editor active="true" />
     <layout>
-      <window_info id="Image Layers" />
-      <window_info id="Designer" />
-      <window_info id="UI Designer" />
-      <window_info id="Capture Tool" />
-      <window_info id="Favorites" side_tool="true" />
-      <window_info active="true" content_ui="combo" id="Project" order="0" visible="true" weight="0.24966443" />
+      <window_info content_ui="combo" id="Project" order="0" visible="true" weight="0.25302014" />
       <window_info id="Structure" order="1" side_tool="true" weight="0.25" />
-      <window_info anchor="bottom" id="Version Control" />
-      <window_info anchor="bottom" id="Terminal" weight="0.3286119" />
-      <window_info anchor="bottom" id="Event Log" side_tool="true" />
-      <window_info anchor="bottom" id="Messages" />
+      <window_info id="Image Layers" order="2" />
+      <window_info id="Designer" order="3" />
+      <window_info id="UI Designer" order="4" />
+      <window_info id="Capture Tool" order="5" />
+      <window_info id="Favorites" order="6" side_tool="true" />
       <window_info anchor="bottom" id="Message" order="0" />
       <window_info anchor="bottom" id="Find" order="1" />
-      <window_info anchor="bottom" id="Run" order="2" weight="0.3286119" />
+      <window_info active="true" anchor="bottom" id="Run" order="2" visible="true" weight="0.32765958" />
       <window_info anchor="bottom" id="Debug" order="3" weight="0.4" />
       <window_info anchor="bottom" id="Cvs" order="4" weight="0.25" />
       <window_info anchor="bottom" id="Inspection" order="5" weight="0.4" />
-      <window_info anchor="bottom" id="TODO" order="6" />
-      <window_info anchor="right" id="Palette" />
-      <window_info anchor="right" id="Theme Preview" />
-      <window_info anchor="right" id="Maven" />
-      <window_info anchor="right" id="Capture Analysis" />
-      <window_info anchor="right" id="Palette&#9;" />
+      <window_info anchor="bottom" id="TODO" order="6" weight="0.32907802" />
+      <window_info anchor="bottom" id="Terminal" order="7" weight="0.32765958" />
+      <window_info anchor="bottom" id="Event Log" order="8" side_tool="true" />
+      <window_info anchor="bottom" id="Version Control" order="9" weight="0.32907802" />
+      <window_info anchor="bottom" id="Messages" order="10" weight="0.32907802" />
       <window_info anchor="right" id="Commander" internal_type="SLIDING" order="0" type="SLIDING" weight="0.4" />
       <window_info anchor="right" id="Ant Build" order="1" weight="0.25" />
       <window_info anchor="right" content_ui="combo" id="Hierarchy" order="2" weight="0.25" />
+      <window_info anchor="right" id="Palette" order="3" />
+      <window_info anchor="right" id="Maven" order="4" />
+      <window_info anchor="right" id="Theme Preview" order="5" />
+      <window_info anchor="right" id="Capture Analysis" order="6" />
+      <window_info anchor="right" id="Palette&#9;" order="7" />
     </layout>
   </component>
   <component name="editorHistoryManager">
-    <entry file="file://$PROJECT_DIR$/src/TypeIntro.java">
-      <provider selected="true" editor-type-id="text-editor">
-        <state>
-          <caret column="22" selection-start-column="22" selection-end-column="22" />
-        </state>
-      </provider>
-    </entry>
+    <entry file="file://$PROJECT_DIR$/src/TypeIntro.java" />
     <entry file="file://$PROJECT_DIR$/src/TypeIntro.kt">
       <provider selected="true" editor-type-id="text-editor">
-        <state relative-caret-position="57">
-          <caret line="3" column="1" lean-forward="true" selection-start-line="3" selection-start-column="1" selection-end-line="3" selection-end-column="1" />
+        <state relative-caret-position="209">
+          <caret line="11" column="32" selection-start-line="11" selection-start-column="32" selection-end-line="11" selection-end-column="32" />
         </state>
       </provider>
     </entry>