diff --git a/docs/labs/regex0.html b/docs/labs/regex0.html
index 9b078959..af81cb63 100644
--- a/docs/labs/regex0.html
+++ b/docs/labs/regex0.html
@@ -43,14 +43,14 @@ <h2>Background</h2>
 <li>Another rule is that square brackets surround a rule that specifies any of a number of characters. If the square brackets surround just alphanumerics, then the pattern matches any of them. So <tt>[brt]</tt> matches a single “<tt>b</tt>”, “<tt>r</tt>”, or “<tt>t</tt>”.
 Inside the brackets you can include
 ranges of symbols separated by dash ("-"), so
-<tt>[A-D]</tt> will match one character, which can be one A, one B, one C,
-or one D.
-You can do this more than once.
+<tt>[A-D]</tt> will match one character in that range,
+which can be one A, one B, one C, or one D.
+You can provide more than one range inside brackets.
 For example,
 the term <tt>[A-Za-z]</tt> will match one character, which can be
 an uppercase Latin letter or a lowercase Latin letter.
-(This text assumes you're not using a long-obsolete character system
-like EBCDIC.)
+(For purposes of our labs we're
+assuming you're not using a long-obsolete character system like EBCDIC.)
 <li>If you follow a pattern with “<tt>&#42;</tt>”, that means
 “<i>0 or more times</i>”.
 In almost all regex implementations (except POSIX BRE),
diff --git a/docs/labs/regex0.js b/docs/labs/regex0.js
index 51d16328..b2ff8981 100644
--- a/docs/labs/regex0.js
+++ b/docs/labs/regex0.js
@@ -31,6 +31,14 @@ info =
         [ "x" ],
       ],
     },
+    {
+      present: String.raw`\[(cat|act)\]`,
+      text: "The pattern '[cat]' or '[act]' matches one latter, a 'c', an 'a', or 't'. That is not what you want.",
+      examples: [
+        [ "[cat]" ],
+        [ "[act]" ],
+      ],
+    },
     {
       absent: "cat",
       text: "The pattern \"cat\" is needed to search for \"cat\".",
@@ -43,7 +51,7 @@ info =
       index: 1,
       text: "You need to mention A.",
       examples: [
-        [ "cat", "B" ],
+        [ null, "B" ],
       ],
     },
     {
@@ -51,8 +59,8 @@ info =
       index: 1,
       text: "Use \"A+\" to indicate \"one or more A\". You could also write \"AA*\".",
       examples: [
-        [ "cat", "A" ],
-        [ "cat", "AA" ],
+        [ null, "A" ],
+        [ null, "AA" ],
       ],
     },
     {
@@ -60,7 +68,7 @@ info =
       index: 1,
       text: "You need to mention B.",
       examples: [
-        [ "cat", "A+" ],
+        [ null, "A+" ],
       ],
     },
     {
@@ -69,7 +77,7 @@ info =
       index: 1,
       text: "Use \"B+\" to indicate \"one or more B\". You could also write \"BB*\".",
       examples: [
-        [ "cat", "A+B" ],
+        [ null, "A+B" ],
       ],
     },
   ],
diff --git a/docs/labs/regex1.js b/docs/labs/regex1.js
index c2fca851..7213ab2c 100644
--- a/docs/labs/regex1.js
+++ b/docs/labs/regex1.js
@@ -5,42 +5,42 @@ info =
       present: "/",
       text: "In JavaScript a constant regular expression is surrounded by forward slashes like /PATTERN/. However, for this exercise we only want the text inside the slashes (the pattern itself).",
       examples: [
-        [ "/" ]
+        [ "/" ],
       ],
     },
     {
       present: "[\"'`]",
       text: "In this exercise we only want the regular expression pattern itself. There is no need to use any kind of quote mark.",
       examples: [
-        [ "'" ]
+        [ "'" ],
       ],
     },
     {
       absent: String.raw`^\^`,
       text: "For input validation, start with '^' to indicate a full match.",
       examples: [
-        [ "(Y|N)" ]
+        [ "(Y|N)" ],
       ],
     },
     {
       present: String.raw`\\[Zz]`,
       text: "The ECMAScript (JavaScript) specification does not support \\Z or \\z.",
       examples: [
-        [ "^Y|N\\z" ]
+        [ "^Y|N\\z" ],
       ],
     },
     {
       absent: String.raw`\$$`,
       text: "For input validation, end with '$' to indicate a full match.",
       examples: [
-        [ "^(Y|N)" ]
+        [ "^(Y|N)" ],
       ],
     },
     {
       absent: String.raw`[\|\[]`,
       text: "Consider using [YN], to match either a Y or an N.",
       examples: [
-        [ "^$" ]
+        [ "^$" ],
       ],
     },
     {
@@ -48,14 +48,14 @@ info =
       absent: String.raw`\(`,
       text: "If you use \"|\" you must parentheses or the precedence will be wrong. For example, \"^A|B$\" accepts anything beginning with A, and it also accepts anything ending with B. That is not what you want.",
       examples: [
-        [ "^Y|N$" ]
+        [ "^Y|N$" ],
       ],
     },
     {
       present: " ",
       text: "Spaces normally match spaces in a regex. Do not use them in this case, because a space is not one of the allowed characters.",
       examples: [
-        [ "^[YN] $" ]
+        [ "^[YN] $" ],
       ],
     },
     {
@@ -63,7 +63,7 @@ info =
       index: 1,
       text: "For input validation, start with '^' to indicate a full match.",
       examples: [
-        [ "^[YN]$", "" ]
+        [ null, "" ],
       ],
     },
     {
@@ -71,7 +71,7 @@ info =
       index: 1,
       text: "For input validation, end with '$' to indicate a full match.",
       examples: [
-        [ "^[YN]$", "^" ]
+        [ null, "^" ],
       ],
     },
     {
@@ -79,87 +79,110 @@ info =
       index: 1,
       text: "You can use [A-Z] to match one uppercase Latin letter (A through Z).",
       examples: [
-        [ "^[YN]$", "^$" ]
+        [ null, "^$" ],
       ],
     },
     {
       present: String.raw`\^\[A-Z\]\*`,
       index: 1,
-      text: "A \"*\" matches one or more, not one or more."
+      text: "A \"*\" matches one or more, not one or more.",
+      examples: [
+        [ null, "^[A-Z]*$" ],
+      ],
     },
     {
       present: String.raw`\(`,
       index: 1,
-      text: "You do not need parentheses to solve this problem."
+      text: "You do not need parentheses to solve this problem.",
+      examples: [
+        [ null, "^([A-Z])+$" ],
+      ],
     },
     {
-      absent: String.raw`(\[A-Z\]\+|
- \[A-Z\]\[A-Z\]\*)`,
+      absent: String.raw`\[A-Z\](\+|\[A-Z\]\*)`,
       index: 1,
       text: "You can use [A-Z]+ to match one or more uppercase Latin letters.",
       examples: [
-        [ "^[YN]$", "^[A-Z]$" ]
+        [ null, "^[A-Z]$" ],
       ],
     },
     {
       present: "True",
       index: 2,
-      text: "Regular expressions are case-sensitive by default; use \"true\"."
+      text: "Regular expressions are case-sensitive by default; use \"true\"",
+      examples: [
+        [ null, null, "True" ],
+      ],
     },
     {
       present: "False",
       index: 2,
-      text: "Regular expressions are case-sensitive by default; use \"false\"."
+      text: "Regular expressions are case-sensitive by default; use \"false\".",
+      examples: [
+        [ null, null, "False" ],
+      ],
     },
     {
       absent: String.raw`\|`,
       index: 2,
-      text: "Use \"|\" to express alternatives."
+      text: "Use \"|\" to express alternatives.",
     },
     {
       present: String.raw`^\^true\|false\$$`,
       index: 2,
-      text: "No. This would match anything beginning with the term true, or anything ending with the term false. Use parenthesis."
+      text: "No. This would match anything beginning with the term true, or anything ending with the term false. Use parenthesis.",
     },
     {
       present: String.raw`^\^false\|true\$$`,
       index: 2,
-      text: "No. This would match anything beginning with the term false, or anything ending with the term true. Use parenthesis."
+      text: "No. This would match anything beginning with the term false, or anything ending with the term true. Use parenthesis.",
     },
     {
       absent: String.raw`\(`,
       index: 2,
-      text: "Use parentheses."
+      text: "Use parentheses.",
     },
     {
       present: String.raw`\$`,
       index: 3,
-      text: "This is Python, not ECMAScript (JavaScript). Use \\Z at the end, not $."
+      text: "This is Python, not ECMAScript (JavaScript). Use \\Z at the end, not $.",
+      examples: [
+        [ null, null, null, "^[A-Z]+$"],
+      ],
     },
     {
       present: String.raw`\\z`,
       index: 3,
-      text: "This is Python. Use \\Z at the end, not \\z."
+      text: "This is Python. Use \\Z at the end, not \\z.",
+      examples: [
+        [ null, null, null, "^[A-Z]+\\z"],
+      ],
     },
     {
       absent: String.raw`^\\A`,
       index: 4,
-      text: "This is Ruby. Use \\A at the beginning."
+      text: "This is Ruby. Use \\A at the beginning.",
+      examples: [
+        [ null, null, null, null, "^[A-Z]+$"],
+      ],
     },
     {
       absent: String.raw`\\z$`,
       index: 4,
-      text: "This is Ruby. Use \\z at the end."
+      text: "This is Ruby. Use \\z at the end.",
+      examples: [
+        [ null, null, null, null, "\\A[A-Z]+$"],
+      ],
     },
     {
       absent: String.raw`\[A-Z\]`,
       index: 4,
-      text: "Use [A-Z] to match one uppercase Latin letter."
+      text: "Use [A-Z] to match one uppercase Latin letter.",
     },
     {
       present: String.raw`\[A-Z\](\*|\+)`,
       index: 4,
-      text: "In this case we are only matching one letter, not many of them. Do not use \"*\" or \"+\" after [A-Z]."
+      text: "In this case we are only matching one letter, not many of them. Do not use \"*\" or \"+\" after [A-Z].",
     },
   ],
   expected: [