[iagno] Yet another tip in help.

[Arnaud B. <arnaudb src gnome org>]

commit d504e083f1d89907bbc58b0833008e007128465a
Author: Arnaud Bonatti <arnaud bonatti gmail com>
Date:   Fri Jan 31 18:41:03 2020 +0100

    Yet another tip in help.

 help/C/figures/alternative-start-1.png | Bin 0 -> 11771 bytes
 help/C/figures/alternative-start-2.png | Bin 0 -> 11066 bytes
 help/C/figures/alternative-start-3.png | Bin 0 -> 11710 bytes
 help/C/figures/alternative-start.png   | Bin 0 -> 12414 bytes
 help/C/figures/positions.xcf           | Bin 0 -> 38184 bytes
 help/C/figures/start.png               | Bin 5330 -> 0 bytes
 help/C/figures/symmetric-start.png     | Bin 0 -> 11148 bytes
 help/C/figures/usual-start.png         | Bin 0 -> 12562 bytes
 help/C/rules.page                      |   6 +-
 help/C/start-position.page             | 123 +++++++++++++++++++++++++++++++++
 help/meson.build                       |   8 ++-
 11 files changed, 133 insertions(+), 4 deletions(-)
---
diff --git a/help/C/figures/alternative-start-1.png b/help/C/figures/alternative-start-1.png
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diff --git a/help/C/figures/positions.xcf b/help/C/figures/positions.xcf
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diff --git a/help/C/figures/symmetric-start.png b/help/C/figures/symmetric-start.png
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diff --git a/help/C/figures/usual-start.png b/help/C/figures/usual-start.png
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diff --git a/help/C/rules.page b/help/C/rules.page
index 29d2fbe..e033cb5 100644
--- a/help/C/rules.page
+++ b/help/C/rules.page
@@ -31,8 +31,8 @@
     <item><p>
       The game begins with four pieces, two light and two dark, placed in the center of the board.
     </p></item>
-    <item><p>Dark goes first.</p></item>
-    <item><p>Dark places a tile on the board in such a way that it traps white tiles between two of the dark 
tiles.</p>
+    <item><p><em>Dark</em> goes first.</p></item>
+    <item><p><em>Dark</em> places a tile on the board in such a way that it traps white tiles between two of 
the dark tiles.</p>
     <note><p>This placement can be horizontal, vertical or diagonal.
     </p></note>
     <p>
@@ -46,7 +46,7 @@
 <table>
  <tr>
   <td>
-  <media type="image" src="figures/start.png" width="200" its:translate="no">
+  <media type="image" src="figures/usual-start.png" width="200" its:translate="no">
     <p its:translate="yes">Start position</p>
   </media>
    </td>
diff --git a/help/C/start-position.page b/help/C/start-position.page
new file mode 100644
index 0000000..996b796
--- /dev/null
+++ b/help/C/start-position.page
@@ -0,0 +1,123 @@
+<page xmlns="http://projectmallard.org/1.0/";
+      type="topic" style="task"
+      id="start-position"
+      xmlns:its="http://www.w3.org/2005/11/its";> <!-- the "its" line is allowing translations for medias -->
+
+  <info>
+    <link type="guide" xref="index#tips" />
+    <revision pkgversion="3.36" version="0.1" date="2020-01-31" status="final"/>
+
+    <credit type="author copyright">
+      <name>Arnaud Bonatti</name>
+      <email>arnaud bonatti gmail com</email>
+      <years>2020</years>
+    </credit>
+
+    <license>
+      <p>Creative Commons Share Alike 3.0</p>
+    </license>
+  </info>
+
+  <title>Vary start position</title>
+
+  <p><app>Reversi</app> allows to start a game with a different initial position than the usual one of the 
reversi game family.</p>
+
+  <section id="varying-start-position">
+    <title>Varying start position</title>
+
+    <p>To enable or disable this option, go in the Start Screen, click on the <gui>Difficulty</gui> button, 
and in the menu that appears, select <gui>Vary start position</gui>.</p>
+
+    <p>If you are playing a <link xref="ai-game">game against the computer</link>, enabling this option will 
start new games with a random position in the six <link xref="#start-positions">possible start 
positions</link>.</p>
+
+    <p>If you are playing a <link xref="2player">two-player game</link>, enabling this option will start new 
games with the <link xref="#human-overture">two-player game overture</link>.</p>
+
+    <p>If the option is disabled, then the usual position of the reversi game family is always used for new 
games. See its description in the list of <link xref="#start-positions">possible start positions</link>.</p>
+  </section>
+
+  <section id="start-positions">
+    <title>Possible start positions</title>
+
+    <p>There are really two possible start positions in <app>Reversi</app>, up to six as their symmetries 
can also be played.</p>
+
+    <p>The two main positions are the following:</p>
+
+    <table>
+      <tr>
+        <td>
+          <media type="image" src="figures/usual-start.png" width="200" its:translate="no">
+            <p its:translate="yes">Usual start position: light-dark, dark-light</p>
+          </media>
+        </td>
+        <td>
+          <media type="image" src="figures/alternative-start.png" width="200" its:translate="no">
+            <p its:translate="yes">Alternative position: dark-light, dark-light</p>
+          </media>
+        </td>
+      </tr>
+      <tr>
+        <td>
+          <p><em>Usual start position</em></p>
+        </td>
+        <td>
+          <p><em>Alternative position</em></p>
+        </td>
+      </tr>
+    </table>
+
+    <p>Their allowed symmetries are the following:</p>
+
+    <table>
+      <tr>
+        <td>
+          <media type="image" src="figures/symmetric-start.png" width="92" its:translate="no">
+            <p its:translate="yes">Only symmetry of the usual start position: dark-light, light-dark</p>
+          </media>
+        </td>
+        <td>
+          <media type="image" src="figures/alternative-start-1.png" width="92" its:translate="no">
+            <p its:translate="yes">First symmetry of the alternative position: dark-dark, light-light</p>
+          </media>
+        </td>
+        <td>
+          <media type="image" src="figures/alternative-start-2.png" width="92" its:translate="no">
+            <p its:translate="yes">Second symmetry of the alternative position: light-dark, light-dark</p>
+          </media>
+        </td>
+        <td>
+          <media type="image" src="figures/alternative-start-3.png" width="92" its:translate="no">
+            <p its:translate="yes">Last symmetry of the alternative position: light-light, dark-dark</p>
+          </media>
+        </td>
+      </tr>
+    </table>
+  </section>
+
+  <section id="human-overture">
+    <title>Two-player game overture</title>
+
+    <p>When playing a <link xref="2player">two-player game</link> with the the <link 
xref="#varying-start-position"><gui>Vary start position</gui></link> option enabled, new games will start 
with a special two-player game overture.</p>
+
+    <p>The board is started empty. The two players are going to place the four initial pieces before 
starting the game.</p>
+
+    <steps>
+      <item>
+        <p><em>Dark</em> goes first, and places the first piece on one of the four central tiles of the 
board.</p>
+      </item>
+      <item>
+        <p><em>Light</em> places one piece in one of the two available positions next to the dark piece.</p>
+      </item>
+      <item>
+        <p><em>Dark</em> then places a piece on one of the two remaining central tiles of the board.</p>
+      </item>
+      <item>
+        <p><em>Light</em> finishes the opening by placing a second piece at the remaining place.</p>
+      </item>
+      <item>
+        <p>The game is then started, following the <link xref="rules">reversi rules</link>.</p>
+      </item>
+    </steps>
+
+    <p>This opening allows the first player to choose if the game will start with a position “in cross” (the 
usual start position or its symmetry) or a “parallel” position (the alternative position or one of its 
symmetries).</p>
+  </section>
+
+</page>
diff --git a/help/meson.build b/help/meson.build
index ccd3c77..e8e63ff 100644
--- a/help/meson.build
+++ b/help/meson.build
@@ -1,10 +1,15 @@
 help_media = [
+    'figures/alternative-start.png',
+    'figures/alternative-start-1.png',
+    'figures/alternative-start-2.png',
+    'figures/alternative-start-3.png',
     'figures/block.png',
     'figures/first.png',
     'figures/iagno-video.ogv',
     'figures/logo32.png',
     'figures/logo.png',
-    'figures/start.png'
+    'figures/symmetric-start.png',
+    'figures/usual-start.png'
 ]
 help_files = [
     '2player.page',
@@ -21,6 +26,7 @@ help_files = [
     'rules.page',
     'shortcuts.page',
     'sound.page',
+    'start-position.page',
     'strategy.page',
     'theme.page',
     'translate.page'