diff --git a/.idea/codeStyleSettings.xml b/.idea/codeStyleSettings.xml
index 05b8113..cab819f 100644
--- a/.idea/codeStyleSettings.xml
+++ b/.idea/codeStyleSettings.xml
@@ -2,7 +2,11 @@
 <project version="4">
   <component name="ProjectCodeStyleSettingsManager">
     <option name="PER_PROJECT_SETTINGS">
-      <value />
+      <value>
+        <XML>
+          <option name="XML_LEGACY_SETTINGS_IMPORTED" value="true" />
+        </XML>
+      </value>
     </option>
     <option name="PREFERRED_PROJECT_CODE_STYLE" value="Default (1)" />
   </component>
diff --git a/.idea/dictionaries/orange.xml b/.idea/dictionaries/orange.xml
index b17435a..5bc621f 100644
--- a/.idea/dictionaries/orange.xml
+++ b/.idea/dictionaries/orange.xml
@@ -2,6 +2,7 @@
   <dictionary name="orange">
     <words>
       <w>anki</w>
+      <w>matplotlib</w>
     </words>
   </dictionary>
 </component>
\ No newline at end of file
diff --git a/.idea/misc.xml b/.idea/misc.xml
index 2533bf7..2e6cdab 100644
--- a/.idea/misc.xml
+++ b/.idea/misc.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
-  <component name="ProjectRootManager" version="2" project-jdk-name="Python 3.3.2 (/usr/bin/python3.3m)" project-jdk-type="Python SDK" />
+  <component name="ProjectRootManager" version="2" project-jdk-name="Python 2.7.5 (/usr/bin/python2.7)" project-jdk-type="Python SDK" />
 </project>
 
diff --git a/.idea/python-exercises.iml b/.idea/python-exercises.iml
index a34a857..6a0cb71 100644
--- a/.idea/python-exercises.iml
+++ b/.idea/python-exercises.iml
@@ -2,7 +2,7 @@
 <module type="PYTHON_MODULE" version="4">
   <component name="NewModuleRootManager">
     <content url="file://$MODULE_DIR$" />
-    <orderEntry type="inheritedJdk" />
+    <orderEntry type="jdk" jdkName="Python 2.7.5 (/usr/bin/python2.7)" jdkType="Python SDK" />
     <orderEntry type="sourceFolder" forTests="false" />
   </component>
 </module>
diff --git a/.idea/workspace.xml b/.idea/workspace.xml
index c8ea75b..6a2c036 100644
--- a/.idea/workspace.xml
+++ b/.idea/workspace.xml
@@ -1,16 +1,15 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
   <component name="ChangeListManager">
-    <list default="true" id="7ab214b9-b539-4600-9149-e54a1f884b51" name="Default" comment="" />
-    <list id="22da2c6d-250c-493f-ac9c-eb57568746ab" name="New changelist" comment="">
-      <change type="NEW" beforePath="" afterPath="$PROJECT_DIR$/.idea/python-exercises.iml" />
-      <change type="NEW" beforePath="" afterPath="$PROJECT_DIR$/.idea/encodings.xml" />
-      <change type="NEW" beforePath="" afterPath="$PROJECT_DIR$/.idea/misc.xml" />
-      <change type="NEW" beforePath="" afterPath="$PROJECT_DIR$/.idea/modules.xml" />
-      <change type="NEW" beforePath="" afterPath="$PROJECT_DIR$/.idea/dictionaries/orange.xml" />
-      <change type="NEW" beforePath="" afterPath="$PROJECT_DIR$/.idea/scopes/scope_settings.xml" />
-      <change type="NEW" beforePath="" afterPath="$PROJECT_DIR$/.idea/vcs.xml" />
+    <list default="true" id="7ab214b9-b539-4600-9149-e54a1f884b51" name="Default" comment="">
+      <change type="MODIFICATION" beforePath="$PROJECT_DIR$/.idea/codeStyleSettings.xml" afterPath="$PROJECT_DIR$/.idea/codeStyleSettings.xml" />
+      <change type="MODIFICATION" beforePath="$PROJECT_DIR$/least-squares.py" afterPath="$PROJECT_DIR$/least-squares.py" />
+      <change type="MODIFICATION" beforePath="$PROJECT_DIR$/.idea/misc.xml" afterPath="$PROJECT_DIR$/.idea/misc.xml" />
+      <change type="MODIFICATION" beforePath="$PROJECT_DIR$/.idea/dictionaries/orange.xml" afterPath="$PROJECT_DIR$/.idea/dictionaries/orange.xml" />
+      <change type="MODIFICATION" beforePath="$PROJECT_DIR$/.idea/python-exercises.iml" afterPath="$PROJECT_DIR$/.idea/python-exercises.iml" />
+      <change type="MODIFICATION" beforePath="$PROJECT_DIR$/.idea/workspace.xml" afterPath="$PROJECT_DIR$/.idea/workspace.xml" />
     </list>
+    <list id="22da2c6d-250c-493f-ac9c-eb57568746ab" name="New changelist" comment="" />
     <ignored path="python-exercises.iws" />
     <ignored path=".idea/workspace.xml" />
     <option name="TRACKING_ENABLED" value="true" />
@@ -32,12 +31,12 @@
   </component>
   <component name="FileEditorManager">
     <leaf>
-      <file leaf-file-name="anki-sin-cos-table.py" pinned="false" current="true" current-in-tab="true">
-        <entry file="file://$PROJECT_DIR$/anki-sin-cos-table.py">
+      <file leaf-file-name="least-squares.py" pinned="false" current="true" current-in-tab="true">
+        <entry file="file://$PROJECT_DIR$/least-squares.py">
           <provider selected="true" editor-type-id="text-editor">
-            <state line="26" column="59" selection-start="669" selection-end="669" vertical-scroll-proportion="0.71014494" vertical-offset="96" max-vertical-offset="510">
+            <state line="12" column="28" selection-start="329" selection-end="329" vertical-scroll-proportion="0.1744186" vertical-offset="105" max-vertical-offset="690">
               <folding>
-                <element signature="e#23#58#0" expanded="true" />
+                <element signature="e#21#68#0" expanded="true" />
               </folding>
             </state>
           </provider>
@@ -57,6 +56,7 @@
     <option name="changedFiles">
       <list>
         <option value="$PROJECT_DIR$/anki-sin-cos-table.py" />
+        <option value="$PROJECT_DIR$/least-squares.py" />
       </list>
     </option>
   </component>
@@ -65,6 +65,28 @@
     <option name="width" value="1280" />
     <option name="height" value="769" />
   </component>
+  <component name="ProjectInspectionProfilesVisibleTreeState">
+    <entry key="Project Default">
+      <profile-state>
+        <expanded-state>
+          <State>
+            <id />
+          </State>
+          <State>
+            <id>Portability issues</id>
+          </State>
+          <State>
+            <id>Python</id>
+          </State>
+        </expanded-state>
+        <selected-state>
+          <State>
+            <id>Buildout</id>
+          </State>
+        </selected-state>
+      </profile-state>
+    </entry>
+  </component>
   <component name="ProjectLevelVcsManager" settingsEditedManually="false">
     <OptionsSetting value="true" id="Add" />
     <OptionsSetting value="true" id="Remove" />
@@ -117,9 +139,9 @@
   <component name="PropertiesComponent">
     <property name="recentsLimit" value="5" />
     <property name="restartRequiresConfirmation" value="true" />
-    <property name="last_opened_file_path" value="$PROJECT_DIR$/anki-sin-cos-table.py" />
+    <property name="last_opened_file_path" value="$PROJECT_DIR$/least-squares.py" />
     <property name="LayoutCode.rearrangeEntriesPython" value="false" />
-    <property name="options.lastSelected" value="preferences.pluginManager" />
+    <property name="options.lastSelected" value="com.jetbrains.python.configuration.PyActiveSdkModuleConfigurable" />
     <property name="options.splitter.main.proportions" value="0.3" />
     <property name="options.splitter.details.proportions" value="0.2" />
     <property name="options.searchVisible" value="true" />
@@ -258,13 +280,13 @@
       <envs>
         <env name="PYTHONUNBUFFERED" value="1" />
       </envs>
-      <option name="SDK_HOME" value="/usr/bin/python3.3m" />
+      <option name="SDK_HOME" value="" />
       <option name="WORKING_DIRECTORY" value="$PROJECT_DIR$" />
-      <option name="IS_MODULE_SDK" value="false" />
+      <option name="IS_MODULE_SDK" value="true" />
       <option name="ADD_CONTENT_ROOTS" value="true" />
       <option name="ADD_SOURCE_ROOTS" value="true" />
       <module name="python-exercises" />
-      <option name="SCRIPT_NAME" value="$PROJECT_DIR$/anki-sin-cos-table.py" />
+      <option name="SCRIPT_NAME" value="$PROJECT_DIR$/least-squares.py" />
       <option name="PARAMETERS" value="" />
       <RunnerSettings RunnerId="PyDebugRunner" />
       <RunnerSettings RunnerId="PythonRunner" />
@@ -309,28 +331,52 @@
       <created>1394405581984</created>
       <updated>1394405581984</updated>
     </task>
-    <option name="localTasksCounter" value="3" />
+    <task id="LOCAL-00003" summary="reduce code line length to 80 characters max">
+      <created>1394440608337</created>
+      <updated>1394440608337</updated>
+    </task>
+    <option name="localTasksCounter" value="4" />
     <servers />
   </component>
+  <component name="TodoView" selected-index="0">
+    <todo-panel id="selected-file">
+      <are-packages-shown value="false" />
+      <are-modules-shown value="false" />
+      <flatten-packages value="false" />
+      <is-autoscroll-to-source value="false" />
+    </todo-panel>
+    <todo-panel id="all">
+      <are-packages-shown value="false" />
+      <are-modules-shown value="false" />
+      <flatten-packages value="false" />
+      <is-autoscroll-to-source value="false" />
+    </todo-panel>
+    <todo-panel id="default-changelist">
+      <are-packages-shown value="false" />
+      <are-modules-shown value="false" />
+      <flatten-packages value="false" />
+      <is-autoscroll-to-source value="false" />
+    </todo-panel>
+  </component>
   <component name="ToolWindowManager">
     <frame x="0" y="31" width="1280" height="769" extended-state="6" />
     <editor active="true" />
     <layout>
-      <window_info id="Messages" active="false" anchor="bottom" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" weight="0.33" sideWeight="0.5" order="-1" side_tool="false" content_ui="tabs" />
-      <window_info id="Changes" active="false" anchor="bottom" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" weight="0.33" sideWeight="0.5" order="-1" side_tool="false" content_ui="tabs" />
-      <window_info id="Terminal" active="false" anchor="bottom" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" weight="0.33" sideWeight="0.5" order="-1" side_tool="false" content_ui="tabs" />
-      <window_info id="TODO" active="false" anchor="bottom" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" weight="0.33" sideWeight="0.5" order="6" side_tool="false" content_ui="tabs" />
-      <window_info id="Find" active="false" anchor="bottom" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" weight="0.32941177" sideWeight="0.5" order="1" side_tool="false" content_ui="tabs" />
-      <window_info id="Structure" active="false" anchor="left" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" weight="0.25" sideWeight="0.5" order="1" side_tool="false" content_ui="tabs" />
-      <window_info id="Project" active="false" anchor="left" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="true" weight="0.16308671" sideWeight="0.5" order="0" side_tool="false" content_ui="combo" />
+      <window_info id="Changes" active="false" anchor="bottom" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" weight="0.32876712" sideWeight="0.5" order="7" side_tool="false" content_ui="tabs" />
+      <window_info id="Terminal" active="false" anchor="bottom" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" weight="0.32876712" sideWeight="0.5" order="7" side_tool="false" content_ui="tabs" />
+      <window_info id="TODO" active="false" anchor="bottom" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" weight="0.32876712" sideWeight="0.5" order="6" side_tool="false" content_ui="tabs" />
+      <window_info id="Structure" active="false" anchor="left" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" weight="0.24980111" sideWeight="0.5" order="1" side_tool="false" content_ui="tabs" />
+      <window_info id="Project" active="false" anchor="left" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="true" weight="0.1627543" sideWeight="0.5" order="0" side_tool="false" content_ui="combo" />
       <window_info id="Debug" active="false" anchor="bottom" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" weight="0.4" sideWeight="0.5" order="3" side_tool="false" content_ui="tabs" />
-      <window_info id="Favorites" active="false" anchor="left" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" weight="0.33" sideWeight="0.5" order="-1" side_tool="true" content_ui="tabs" />
-      <window_info id="Event Log" active="false" anchor="bottom" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" weight="0.32941177" sideWeight="0.5" order="-1" side_tool="true" content_ui="tabs" />
-      <window_info id="Run" active="false" anchor="bottom" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" weight="0.32876712" sideWeight="0.5" order="2" side_tool="false" content_ui="tabs" />
-      <window_info id="Version Control" active="false" anchor="bottom" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" weight="0.33" sideWeight="0.5" order="-1" side_tool="false" content_ui="tabs" />
+      <window_info id="Favorites" active="false" anchor="left" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" weight="0.33" sideWeight="0.5" order="2" side_tool="true" content_ui="tabs" />
+      <window_info id="Event Log" active="false" anchor="bottom" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" weight="0.32941177" sideWeight="0.5" order="7" side_tool="true" content_ui="tabs" />
+      <window_info id="Run" active="false" anchor="bottom" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="true" weight="0.32794118" sideWeight="0.5" order="2" side_tool="false" content_ui="tabs" />
+      <window_info id="Version Control" active="false" anchor="bottom" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" weight="0.32876712" sideWeight="0.5" order="7" side_tool="false" content_ui="tabs" />
       <window_info id="Cvs" active="false" anchor="bottom" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" weight="0.25" sideWeight="0.5" order="4" side_tool="false" content_ui="tabs" />
       <window_info id="Message" active="false" anchor="bottom" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" weight="0.33" sideWeight="0.5" order="0" side_tool="false" content_ui="tabs" />
+      <window_info id="Find" active="false" anchor="bottom" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" weight="0.32941177" sideWeight="0.5" order="1" side_tool="false" content_ui="tabs" />
       <window_info id="Ant Build" active="false" anchor="right" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" weight="0.25" sideWeight="0.5" order="1" side_tool="false" content_ui="tabs" />
+      <window_info id="Messages" active="false" anchor="bottom" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" weight="0.33" sideWeight="0.5" order="7" side_tool="false" content_ui="tabs" />
       <window_info id="Commander" active="false" anchor="right" auto_hide="false" internal_type="SLIDING" type="SLIDING" visible="false" weight="0.4" sideWeight="0.5" order="0" side_tool="false" content_ui="tabs" />
       <window_info id="Inspection" active="false" anchor="bottom" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" weight="0.4" sideWeight="0.5" order="5" side_tool="false" content_ui="tabs" />
       <window_info id="Hierarchy" active="false" anchor="right" auto_hide="false" internal_type="DOCKED" type="DOCKED" visible="false" weight="0.25" sideWeight="0.5" order="2" side_tool="false" content_ui="combo" />
@@ -350,25 +396,77 @@
     </option>
     <MESSAGE value="Restructure" />
     <MESSAGE value="include trigonometric function values for a step size of pi/6" />
-    <option name="LAST_COMMIT_MESSAGE" value="include trigonometric function values for a step size of pi/6" />
+    <MESSAGE value="reduce code line length to 80 characters max" />
+    <option name="LAST_COMMIT_MESSAGE" value="reduce code line length to 80 characters max" />
   </component>
   <component name="XDebuggerManager">
     <breakpoint-manager>
-      <breakpoints>
-        <line-breakpoint type="python-line">
-          <url>file://$PROJECT_DIR$/anki-sin-cos-table.py</url>
-          <line>25</line>
-        </line-breakpoint>
-      </breakpoints>
       <option name="time" value="1" />
     </breakpoint-manager>
   </component>
   <component name="editorHistoryManager">
     <entry file="file://$PROJECT_DIR$/anki-sin-cos-table.py">
       <provider selected="true" editor-type-id="text-editor">
-        <state line="26" column="59" selection-start="669" selection-end="669" vertical-scroll-proportion="0.71014494" vertical-offset="96" max-vertical-offset="510">
+        <state line="22" column="28" selection-start="487" selection-end="487" vertical-scroll-proportion="0.0" vertical-offset="270" max-vertical-offset="525">
+          <folding>
+            <element signature="e#23#58#0" expanded="false" />
+          </folding>
+        </state>
+      </provider>
+    </entry>
+    <entry file="file://$APPLICATION_PLUGINS_DIR$/scratches/scratch.txt">
+      <provider selected="true" editor-type-id="text-editor">
+        <state line="0" column="0" selection-start="0" selection-end="0" vertical-scroll-proportion="0.0" vertical-offset="0" max-vertical-offset="90">
+          <folding />
+        </state>
+      </provider>
+    </entry>
+    <entry file="file://$PROJECT_DIR$/anki-sin-cos-table.py">
+      <provider selected="true" editor-type-id="text-editor">
+        <state line="22" column="28" selection-start="487" selection-end="487" vertical-scroll-proportion="0.0" vertical-offset="270" max-vertical-offset="525">
+          <folding>
+            <element signature="e#23#58#0" expanded="false" />
+          </folding>
+        </state>
+      </provider>
+    </entry>
+    <entry file="file://$APPLICATION_PLUGINS_DIR$/scratches/scratch.txt">
+      <provider selected="true" editor-type-id="text-editor">
+        <state line="0" column="0" selection-start="0" selection-end="0" vertical-scroll-proportion="0.0" vertical-offset="0" max-vertical-offset="90">
+          <folding />
+        </state>
+      </provider>
+    </entry>
+    <entry file="file://$PROJECT_DIR$/anki-sin-cos-table.py">
+      <provider selected="true" editor-type-id="text-editor">
+        <state line="26" column="59" selection-start="669" selection-end="669" vertical-scroll-proportion="0.0" vertical-offset="60" max-vertical-offset="510">
+          <folding>
+            <element signature="e#23#58#0" expanded="false" />
+          </folding>
+        </state>
+      </provider>
+    </entry>
+    <entry file="file://$PROJECT_DIR$/anki-sin-cos-table.py">
+      <provider selected="true" editor-type-id="text-editor">
+        <state line="22" column="28" selection-start="487" selection-end="487" vertical-scroll-proportion="0.5254777" vertical-offset="0" max-vertical-offset="628">
+          <folding>
+            <element signature="e#23#58#0" expanded="false" />
+          </folding>
+        </state>
+      </provider>
+    </entry>
+    <entry file="file://$APPLICATION_PLUGINS_DIR$/scratches/scratch.txt">
+      <provider selected="true" editor-type-id="text-editor">
+        <state line="0" column="0" selection-start="0" selection-end="0" vertical-scroll-proportion="0.0" vertical-offset="0" max-vertical-offset="630">
+          <folding />
+        </state>
+      </provider>
+    </entry>
+    <entry file="file://$PROJECT_DIR$/least-squares.py">
+      <provider selected="true" editor-type-id="text-editor">
+        <state line="12" column="28" selection-start="329" selection-end="329" vertical-scroll-proportion="0.1744186" vertical-offset="105" max-vertical-offset="690">
           <folding>
-            <element signature="e#23#58#0" expanded="true" />
+            <element signature="e#21#68#0" expanded="true" />
           </folding>
         </state>
       </provider>