diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..5c99835
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,5 @@
+# NOTE: Thinking about adding files created by your operating system, IDE,
+# or text editor here? Don't! Add them to your per-user .gitignore instead.
+
+
+/src/.phutil_module_cache
diff --git a/rsrc/css/light-rtl.css b/rsrc/css/light-rtl.css
new file mode 100644
index 0000000..4a2474e
--- /dev/null
+++ b/rsrc/css/light-rtl.css
@@ -0,0 +1,19 @@
+/**
+ * @provides light-rtl
+ */
+
+
+.light-rtl-righttoleft .phabricator-remarkup {
+    text-align: right;
+    direction: rtl;
+}
+
+.light-rtl-righttoleft .phabricator-remarkup ul.remarkup-list,
+.light-rtl-righttoleft .phabricator-remarkup ol.remarkup-list {
+    margin: 12px 30px 12px 0;
+}
+
+
+.light-rtl-righttoleft div.phabricator-remarkup > *:last-child {
+    margin-bottom: 0;
+}
diff --git a/src/__phutil_library_init__.php b/src/__phutil_library_init__.php
new file mode 100644
index 0000000..f743ae5
--- /dev/null
+++ b/src/__phutil_library_init__.php
@@ -0,0 +1,3 @@
+<?php
+
+phutil_register_library('light-rtl', __FILE__);
diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
new file mode 100644
index 0000000..7083e43
--- /dev/null
+++ b/src/__phutil_library_map__.php
@@ -0,0 +1,22 @@
+<?php
+
+/**
+ * This file is automatically generated. Use 'arc liberate' to rebuild it.
+ *
+ * @generated
+ * @phutil-library-version 2
+ */
+phutil_register_library_map(array(
+  '__library_version__' => 2,
+  'class' => array(
+    'LightweightRTLApplication' => 'application/LightweightRTLApplication.php',
+    'LightweightRTLCelerityResources' => 'celerity/LightweightRTLCelerityResources.php',
+    'LightweightRTLMainMenuBarExtension' => 'engineextension/LightweightRTLMainMenuBarExtension.php',
+  ),
+  'function' => array(),
+  'xmap' => array(
+    'LightweightRTLApplication' => 'PhabricatorApplication',
+    'LightweightRTLCelerityResources' => 'CelerityResourcesOnDisk',
+    'LightweightRTLMainMenuBarExtension' => 'PhabricatorMainMenuBarExtension',
+  ),
+));
diff --git a/src/application/LightweightRTLApplication.php b/src/application/LightweightRTLApplication.php
new file mode 100644
index 0000000..004746d
--- /dev/null
+++ b/src/application/LightweightRTLApplication.php
@@ -0,0 +1,13 @@
+<?php
+
+final class LightweightRTLApplication extends PhabricatorApplication {
+
+  public function getName() {
+    return pht("Lightweight Right-to-Left Switcher");
+  }
+
+
+  public function isLaunchable() {
+    return false;
+  }
+}
diff --git a/src/celerity/LightweightRTLCelerityResources.php b/src/celerity/LightweightRTLCelerityResources.php
new file mode 100644
index 0000000..904e943
--- /dev/null
+++ b/src/celerity/LightweightRTLCelerityResources.php
@@ -0,0 +1,18 @@
+<?php
+
+final class LightweightRTLCelerityResources extends CelerityResourcesOnDisk {
+  public function getName() {
+    return 'lightwtrtl';
+  }
+
+  public function getPathToResources() {
+    return $this->getPath('../rsrc');
+  }
+  public function getPathToMap() {
+    return $this->getPath('celerity/map.php');
+  }
+
+  private function getPath($to_file) {
+    return (phutil_get_library_root('light-rtl')).'/'.$to_file;
+  }
+}
diff --git a/src/celerity/map.php b/src/celerity/map.php
new file mode 100644
index 0000000..3a514eb
--- /dev/null
+++ b/src/celerity/map.php
@@ -0,0 +1,17 @@
+<?php
+
+/**
+ * This file is automatically generated. Use 'bin/celerity map' to rebuild it.
+ *
+ * @generated
+ */
+return array(
+  'names' => array(
+    'css/light-rtl.css' => 'ef50d5d5',
+  ),
+  'symbols' => array(
+    'light-rtl' => 'ef50d5d5',
+  ),
+  'requires' => array(),
+  'packages' => array(),
+);
diff --git a/src/engineextension/LightweightRTLMainMenuBarExtension.php b/src/engineextension/LightweightRTLMainMenuBarExtension.php
new file mode 100644
index 0000000..46d8f90
--- /dev/null
+++ b/src/engineextension/LightweightRTLMainMenuBarExtension.php
@@ -0,0 +1,30 @@
+<?php
+
+final class LightweightRTLMainMenuBarExtension
+  extends PhabricatorMainMenuBarExtension {
+
+    const MAINMENUBARKEY = 'LIGHTWTRTL';
+
+    public function buildMainMenus() {
+
+      require_celerity_resource('light-rtl', 'lightwtrtl');
+
+      return array(
+        id(new PHUIButtonView())
+          ->setHref('#')
+          ->setTag('a')
+          ->addClass('phabricator-core-login-button')
+          ->setText(pht('Right-To-Left'))
+          ->setNoCSS(true)
+
+          ->addSigil('has-tooltip')
+          ->addSigil('jx-toggle-class')
+          ->setMetadata(array(
+            'tip' => pht('Switch text direction'),
+            'map' => array(
+              'phabricator-standard-page' => 'light-rtl-righttoleft',
+            ))),
+      );
+    }
+
+}