--- a/doc/html/logic_programming/rules/forward_chaining.html
+++ b/doc/html/logic_programming/rules/forward_chaining.html
@@ -132,14 +132,14 @@
 <p>This example will figure out the paternal ancestry of individuals given a list
 of starting statements about who the sons of each father are.  (Daughters and
 mothers are omitted to keep the example brief).  These facts are stored in a
-<a class="reference external" href="../../knowledge_bases/fact_bases.html">fact base</a> called <tt class="docutils literal"><span class="pre">family1</span></tt> as <tt class="docutils literal"><span class="pre">son_of(son,</span> <span class="pre">father)</span></tt>:</p>
+<a class="reference external" href="../../knowledge_bases/fact_bases.html">fact base</a> called <tt class="docutils literal">family1</tt> as <tt class="docutils literal">son_of(son, father)</tt>:</p>
 <pre class="literal-block">
 1  son_of(david, bruce)
 2  son_of(bruce, thomas)
 3  son_of(thomas, frederik)
 4  son_of(frederik, hiram)
 </pre>
-<p>We want to derive <tt class="docutils literal"><span class="pre">father_son</span></tt> relationships of the following form:</p>
+<p>We want to derive <tt class="docutils literal">father_son</tt> relationships of the following form:</p>
 <pre class="literal-block">
 father_son($father, $son, $prefix)
 </pre>
@@ -154,8 +154,8 @@
 <tr class="field"><th class="field-name">$father:</th><td class="field-body">is the name of the father (e.g., bruce)</td>
 </tr>
 <tr class="field"><th class="field-name">$prefix:</th><td class="field-body">is a tuple of prefixes before the 'father' and 'son' titles to
-indicate the number of generations (e.g., <tt class="docutils literal"><span class="pre">()</span></tt> for direct
-father_son relationships, <tt class="docutils literal"><span class="pre">(grand)</span></tt>, <tt class="docutils literal"><span class="pre">(great,</span> <span class="pre">grand)</span></tt>, etc).</td>
+indicate the number of generations (e.g., <tt class="docutils literal">()</tt> for direct
+father_son relationships, <tt class="docutils literal">(grand)</tt>, <tt class="docutils literal">(great, grand)</tt>, etc).</td>
 </tr>
 </tbody>
 </table>
@@ -184,7 +184,7 @@
 <div class="section" id="step-1-direct-father-son">
 <h2>Step 1: Direct_father_son</h2>
 <p>First we need to establish the direct father_son relationships (those whose
-<tt class="docutils literal"><span class="pre">$prefix</span></tt> is <tt class="docutils literal"><span class="pre">()</span></tt>):</p>
+<tt class="docutils literal">$prefix</tt> is <tt class="docutils literal">()</tt>):</p>
 <pre class="literal-block">
 1  direct_father_son
 2      foreach
@@ -196,12 +196,12 @@
 <h3>The Use of Pattern Variables</h3>
 <p>This demonstrates how <a class="reference external" href="../pattern_matching/pattern_variables.html">pattern variables</a> are used to transfer values from
 one statement within a rule into another statement within the rule.</p>
-<p>This rule has a single statement in its <tt class="docutils literal"><span class="pre">foreach</span></tt> clause (on line 3).  This
-statement matches all four <tt class="docutils literal"><span class="pre">son_of</span></tt> facts, so the rule succeeds four times;
-but with different bindings for the <tt class="docutils literal"><span class="pre">$son</span></tt> and <tt class="docutils literal"><span class="pre">$father</span></tt> pattern variables.
-This causes different facts to be asserted when the same <tt class="docutils literal"><span class="pre">assert</span></tt> clause (on
+<p>This rule has a single statement in its <tt class="docutils literal">foreach</tt> clause (on line 3).  This
+statement matches all four <tt class="docutils literal">son_of</tt> facts, so the rule succeeds four times;
+but with different bindings for the <tt class="docutils literal">$son</tt> and <tt class="docutils literal">$father</tt> pattern variables.
+This causes different facts to be asserted when the same <tt class="docutils literal">assert</tt> clause (on
 line 5) is run four times; because each time line 5 is run, the values for
-<tt class="docutils literal"><span class="pre">$son</span></tt> and <tt class="docutils literal"><span class="pre">$father</span></tt> are transferred from the statement on line 3 to the
+<tt class="docutils literal">$son</tt> and <tt class="docutils literal">$father</tt> are transferred from the statement on line 3 to the
 statement on line 5.</p>
 <p>When the rule fires matching line 3 to:</p>
 <pre class="literal-block">
@@ -219,8 +219,8 @@
 <pre class="literal-block">
 6  father_son(thomas, bruce, ())
 </pre>
-<p>The rule fires twice more for the remaining <tt class="docutils literal"><span class="pre">son_of</span></tt> facts, asserting
-two more <tt class="docutils literal"><span class="pre">father_son</span></tt> relationships.  So this rule adds a total of four
+<p>The rule fires twice more for the remaining <tt class="docutils literal">son_of</tt> facts, asserting
+two more <tt class="docutils literal">father_son</tt> relationships.  So this rule adds a total of four
 new facts:</p>
 <pre class="literal-block">
 5  father_son(bruce, david, ())
@@ -244,20 +244,20 @@
 </pre>
 <div class="section" id="the-use-of-backtracking">
 <h3>The Use of Backtracking</h3>
-<p>The <tt class="docutils literal"><span class="pre">grand_father_son</span></tt> <a class="reference external" href="index.html">rule</a> is run for all combinations of <tt class="docutils literal"><span class="pre">father_son</span></tt>
-<a class="reference external" href="../../knowledge_bases/fact_bases.html#facts">facts</a> that satisfy the two <tt class="docutils literal"><span class="pre">foreach</span></tt> <a class="reference external" href="../statements.html">statements</a> (on lines 8 and 9) and
-<a class="reference external" href="../../using_pyke/adding_facts.html">asserts</a> a <tt class="docutils literal"><span class="pre">(grand)</span></tt> <tt class="docutils literal"><span class="pre">father_son</span></tt> statement (on line 11) for each
+<p>The <tt class="docutils literal">grand_father_son</tt> <a class="reference external" href="index.html">rule</a> is run for all combinations of <tt class="docutils literal">father_son</tt>
+<a class="reference external" href="../../knowledge_bases/fact_bases.html#facts">facts</a> that satisfy the two <tt class="docutils literal">foreach</tt> <a class="reference external" href="../statements.html">statements</a> (on lines 8 and 9) and
+<a class="reference external" href="../../using_pyke/adding_facts.html">asserts</a> a <tt class="docutils literal">(grand)</tt> <tt class="docutils literal">father_son</tt> statement (on line 11) for each
 combination.</p>
 <p>This rule is a good example for <a class="reference external" href="index.html#backtracking">backtracking</a> and will help later in your
 understanding of backtracking with <a class="reference external" href="backward_chaining.html">backward-chaining</a>.  So let's follow the
 backtracking in the execution of this rule.</p>
-<p>The <tt class="docutils literal"><span class="pre">foreach</span></tt> clause has two statements (on lines 8 and 9) in it that are
-both looking for <tt class="docutils literal"><span class="pre">father_son</span></tt> facts with a prefix of <tt class="docutils literal"><span class="pre">()</span></tt>:</p>
+<p>The <tt class="docutils literal">foreach</tt> clause has two statements (on lines 8 and 9) in it that are
+both looking for <tt class="docutils literal">father_son</tt> facts with a prefix of <tt class="docutils literal">()</tt>:</p>
 <pre class="literal-block">
 8  family1.father_son($father, $grand_son, ())
 9  family1.father_son($grand_father, $father, ())
 </pre>
-<p>These will be matched to the following <tt class="docutils literal"><span class="pre">family1</span></tt> facts (facts 5 through 8):</p>
+<p>These will be matched to the following <tt class="docutils literal">family1</tt> facts (facts 5 through 8):</p>
 <pre class="literal-block">
 5  father_son(bruce, david, ())
 6  father_son(thomas, bruce, ())
@@ -266,13 +266,13 @@
 </pre>
 <p>Pyke starts at the top of the list of premises and looks for a match for the
 first premise (on line 8).  This matches fact 5, so the first premise
-succeeds, binding <tt class="docutils literal"><span class="pre">$father</span></tt> to <tt class="docutils literal"><span class="pre">bruce</span></tt>:</p>
+succeeds, binding <tt class="docutils literal">$father</tt> to <tt class="docutils literal">bruce</tt>:</p>
 <pre class="literal-block">
 8  family1.father_son($father, $grand_son, ())    =&gt; fact 5, SUCCESS
 9  family1.father_son($grand_father, $father, ())
 </pre>
 <p><em>Success</em> means go <em>down</em>, so Pyke goes to the next premise on line 9.  This
-succeeds with fact 6 (because <tt class="docutils literal"><span class="pre">$father</span></tt> is bound to <tt class="docutils literal"><span class="pre">bruce</span></tt>):</p>
+succeeds with fact 6 (because <tt class="docutils literal">$father</tt> is bound to <tt class="docutils literal">bruce</tt>):</p>
 <pre class="literal-block">
 8  family1.father_son($father, $grand_son, ())    =&gt; fact 5
 9  family1.father_son($grand_father, $father, ()) =&gt; fact 6, SUCCESS
@@ -291,15 +291,15 @@
 <a class="reference external" href="backward_chaining.html">backward-chaining</a> rules.</p>
 </div>
 <p>So Pyke <em>fails</em> back <em>up</em> to the second premise and looks for another
-<tt class="docutils literal"><span class="pre">father_son</span></tt> after fact 6 with <tt class="docutils literal"><span class="pre">bruce</span></tt> as the first argument.  This
+<tt class="docutils literal">father_son</tt> after fact 6 with <tt class="docutils literal">bruce</tt> as the first argument.  This
 fails:</p>
 <pre class="literal-block">
 8  family1.father_son($father, $grand_son, ())    =&gt; fact 5
 9  family1.father_son($grand_father, $father, ()) =&gt; FAILS
 </pre>
 <p><em>Fail</em> means go <em>up</em>, so Pyke goes up to the first premise and looks for
-another <tt class="docutils literal"><span class="pre">father_son</span></tt> after fact 5, which succeeds for fact 6, binding
-<tt class="docutils literal"><span class="pre">$father</span></tt> to <tt class="docutils literal"><span class="pre">thomas</span></tt>:</p>
+another <tt class="docutils literal">father_son</tt> after fact 5, which succeeds for fact 6, binding
+<tt class="docutils literal">$father</tt> to <tt class="docutils literal">thomas</tt>:</p>
 <pre class="literal-block">
 8  family1.father_son($father, $grand_son, ())    =&gt; fact 6, SUCCESS
 9  family1.father_son($grand_father, $father, ())
@@ -324,13 +324,13 @@
 <p><em>Fail</em> means go <em>up</em>, so Pyke goes back to the first premise and continues
 looking for another match after fact 6.  (Since fact 7 is just like the last
 case, we'll skip matching fact 7 and go straight to the last fact, fact 8).
-The match to fact 8 succeeds, binding <tt class="docutils literal"><span class="pre">$father</span></tt> to <tt class="docutils literal"><span class="pre">hiram</span></tt>:</p>
+The match to fact 8 succeeds, binding <tt class="docutils literal">$father</tt> to <tt class="docutils literal">hiram</tt>:</p>
 <pre class="literal-block">
 8  family1.father_son($father, $grand_son, ())    =&gt; fact 8, SUCCESS
 9  family1.father_son($grand_father, $father, ())
 </pre>
 <p><em>Success</em> means go <em>down</em>, so Pyke goes to the second premise and looks for a
-<tt class="docutils literal"><span class="pre">father_son</span></tt> for <tt class="docutils literal"><span class="pre">hiram</span></tt>.  This fails:</p>
+<tt class="docutils literal">father_son</tt> for <tt class="docutils literal">hiram</tt>.  This fails:</p>
 <pre class="literal-block">
 8  family1.father_son($father, $grand_son, ())    =&gt; fact 8
 9  family1.father_son($grand_father, $father, ()) =&gt; FAILS
@@ -345,12 +345,12 @@
 so the <em>rule</em> fails and Pyke is done processing it.</p>
 <div class="important">
 <p class="first admonition-title">Important</p>
-<p>Note that the <em>last</em> statement in the <tt class="docutils literal"><span class="pre">foreach</span></tt> clause may <em>succeed</em>
-multiple times (which fires the <tt class="docutils literal"><span class="pre">assert</span></tt> clause multiple times).</p>
-<p class="last">But the <em>first</em> statement in the <tt class="docutils literal"><span class="pre">foreach</span></tt> clause may only <em>fail</em> once.
+<p>Note that the <em>last</em> statement in the <tt class="docutils literal">foreach</tt> clause may <em>succeed</em>
+multiple times (which fires the <tt class="docutils literal">assert</tt> clause multiple times).</p>
+<p class="last">But the <em>first</em> statement in the <tt class="docutils literal">foreach</tt> clause may only <em>fail</em> once.
 When that happens, the whole rule fails and the show's over for this rule!</p>
 </div>
-<p>So running the <tt class="docutils literal"><span class="pre">grand_father_son</span></tt> rule results in addition of these three
+<p>So running the <tt class="docutils literal">grand_father_son</tt> rule results in addition of these three
 facts:</p>
 <pre class="literal-block">
 9  father_son(thomas, david, (grand))
@@ -375,13 +375,13 @@
 <div class="note">
 <p class="first admonition-title">Note</p>
 <p class="last">Note how the $prefixes for the statement on line 15 are specified as
-<tt class="docutils literal"><span class="pre">($prefix1,</span> <span class="pre">*$rest_prefixes)</span></tt>, rather than just <tt class="docutils literal"><span class="pre">$prefix</span></tt>.
-This is done so that it does <em>not</em> match <tt class="docutils literal"><span class="pre">()</span></tt>.  (But it will still match
-<tt class="docutils literal"><span class="pre">(grand)</span></tt> by binding <tt class="docutils literal"><span class="pre">$rest_prefixes</span></tt> to <tt class="docutils literal"><span class="pre">()</span></tt>).</p>
+<tt class="docutils literal">($prefix1, *$rest_prefixes)</tt>, rather than just <tt class="docutils literal">$prefix</tt>.
+This is done so that it does <em>not</em> match <tt class="docutils literal">()</tt>.  (But it will still match
+<tt class="docutils literal">(grand)</tt> by binding <tt class="docutils literal">$rest_prefixes</tt> to <tt class="docutils literal">()</tt>).</p>
 </div>
 <p>This is the only rule that can be recursive.  As this rule <a class="reference external" href="../../using_pyke/adding_facts.html">asserts</a> new <a class="reference external" href="../../knowledge_bases/fact_bases.html#facts">facts</a>,
 those facts may be used by the same rule (by matching the statement on line
-15) to produce even more great, great, ... <tt class="docutils literal"><span class="pre">father_son</span></tt> relationships.</p>
+15) to produce even more great, great, ... <tt class="docutils literal">father_son</tt> relationships.</p>
 <div class="section" id="recursive-rules">
 <h3>Recursive Rules</h3>
 <p>Running this rule normally will assert the following two facts:</p>
@@ -391,15 +391,15 @@
 </pre>
 <p>But, since these facts may also be used by the same rule (on line 15), Pyke
 checks each one by trying to run the rule again just for that new fact.</p>
-<p>Trying this for the first new fact: <tt class="docutils literal"><span class="pre">father_son(frederik,</span> <span class="pre">david,</span>
-<span class="pre">(great,</span> <span class="pre">grand))</span></tt> fails to find anything because <tt class="docutils literal"><span class="pre">david</span></tt> is not a father.</p>
-<p>Trying this for the second new fact: <tt class="docutils literal"><span class="pre">father_son(hiram,</span> <span class="pre">bruce,</span> <span class="pre">(great,</span>
-<span class="pre">grand))</span></tt> results in one more new fact:</p>
+<p>Trying this for the first new fact: <tt class="docutils literal">father_son(frederik, david,
+(great, grand))</tt> fails to find anything because <tt class="docutils literal">david</tt> is not a father.</p>
+<p>Trying this for the second new fact: <tt class="docutils literal">father_son(hiram, bruce, (great,
+grand))</tt> results in one more new fact:</p>
 <pre class="literal-block">
 14 father_son(hiram, david, (great, great, grand))
 </pre>
 <p>Now this last new fact is tried again with this rule, which fails again
-because <tt class="docutils literal"><span class="pre">david</span></tt> is not a father.</p>
+because <tt class="docutils literal">david</tt> is not a father.</p>
 <p>So at this point Pyke is finished with this rule.  The rule ended up firing
 three times, asserting:</p>
 <pre class="literal-block">