diff --git a/ql/lib/tutorial.qll b/ql/lib/tutorial.qll
new file mode 100644
index 00000000000..8cb1797a532
--- /dev/null
+++ b/ql/lib/tutorial.qll
@@ -0,0 +1,1207 @@
+/**
+ * This library is used in the QL detective tutorials.
+ *
+ * Note: Data is usually stored in a separate database and the QL libraries only contain predicates,
+ * but for this tutorial both the data and the predicates are stored in the library.
+ */
+class Person extends string {
+  Person() {
+    this = "Ronil" or
+    this = "Dina" or
+    this = "Ravi" or
+    this = "Bruce" or
+    this = "Jo" or
+    this = "Aida" or
+    this = "Esme" or
+    this = "Charlie" or
+    this = "Fred" or
+    this = "Meera" or
+    this = "Maya" or
+    this = "Chad" or
+    this = "Tiana" or
+    this = "Laura" or
+    this = "George" or
+    this = "Will" or
+    this = "Mary" or
+    this = "Almira" or
+    this = "Susannah" or
+    this = "Rhoda" or
+    this = "Cynthia" or
+    this = "Eunice" or
+    this = "Olive" or
+    this = "Virginia" or
+    this = "Angeline" or
+    this = "Helen" or
+    this = "Cornelia" or
+    this = "Harriet" or
+    this = "Mahala" or
+    this = "Abby" or
+    this = "Margaret" or
+    this = "Deb" or
+    this = "Minerva" or
+    this = "Severus" or
+    this = "Lavina" or
+    this = "Adeline" or
+    this = "Cath" or
+    this = "Elisa" or
+    this = "Lucretia" or
+    this = "Anne" or
+    this = "Eleanor" or
+    this = "Joanna" or
+    this = "Adam" or
+    this = "Agnes" or
+    this = "Rosanna" or
+    this = "Clara" or
+    this = "Melissa" or
+    this = "Amy" or
+    this = "Isabel" or
+    this = "Jemima" or
+    this = "Cordelia" or
+    this = "Melinda" or
+    this = "Delila" or
+    this = "Jeremiah" or
+    this = "Elijah" or
+    this = "Hester" or
+    this = "Walter" or
+    this = "Oliver" or
+    this = "Hugh" or
+    this = "Aaron" or
+    this = "Reuben" or
+    this = "Eli" or
+    this = "Amos" or
+    this = "Augustus" or
+    this = "Theodore" or
+    this = "Ira" or
+    this = "Timothy" or
+    this = "Cyrus" or
+    this = "Horace" or
+    this = "Simon" or
+    this = "Asa" or
+    this = "Frank" or
+    this = "Nelson" or
+    this = "Leonard" or
+    this = "Harrison" or
+    this = "Anthony" or
+    this = "Louis" or
+    this = "Milton" or
+    this = "Noah" or
+    this = "Cornelius" or
+    this = "Abdul" or
+    this = "Warren" or
+    this = "Harvey" or
+    this = "Dennis" or
+    this = "Wesley" or
+    this = "Sylvester" or
+    this = "Gilbert" or
+    this = "Sullivan" or
+    this = "Edmund" or
+    this = "Wilson" or
+    this = "Perry" or
+    this = "Matthew" or
+    this = "Simba" or
+    this = "Nala" or
+    this = "Rafiki" or
+    this = "Shenzi" or
+    this = "Ernest" or
+    this = "Gertrude" or
+    this = "Oscar" or
+    this = "Lilian" or
+    this = "Raymond" or
+    this = "Elgar" or
+    this = "Elmer" or
+    this = "Herbert" or
+    this = "Maude" or
+    this = "Mae" or
+    this = "Otto" or
+    this = "Edwin" or
+    this = "Ophelia" or
+    this = "Parsley" or
+    this = "Sage" or
+    this = "Rosemary" or
+    this = "Thyme" or
+    this = "Garfunkel" or
+    this = "King Basil" or
+    this = "Stephen"
+  }
+
+  /** Gets the hair color of the person. If the person is bald, there is no result. */
+  string getHairColor() {
+    this = "Ronil" and result = "black"
+    or
+    this = "Dina" and result = "black"
+    or
+    this = "Ravi" and result = "black"
+    or
+    this = "Bruce" and result = "brown"
+    or
+    this = "Jo" and result = "red"
+    or
+    this = "Aida" and result = "blond"
+    or
+    this = "Esme" and result = "blond"
+    or
+    this = "Fred" and result = "gray"
+    or
+    this = "Meera" and result = "brown"
+    or
+    this = "Maya" and result = "brown"
+    or
+    this = "Chad" and result = "brown"
+    or
+    this = "Tiana" and result = "black"
+    or
+    this = "Laura" and result = "blond"
+    or
+    this = "George" and result = "blond"
+    or
+    this = "Will" and result = "blond"
+    or
+    this = "Mary" and result = "blond"
+    or
+    this = "Almira" and result = "black"
+    or
+    this = "Susannah" and result = "blond"
+    or
+    this = "Rhoda" and result = "blond"
+    or
+    this = "Cynthia" and result = "gray"
+    or
+    this = "Eunice" and result = "white"
+    or
+    this = "Olive" and result = "brown"
+    or
+    this = "Virginia" and result = "brown"
+    or
+    this = "Angeline" and result = "red"
+    or
+    this = "Helen" and result = "white"
+    or
+    this = "Cornelia" and result = "gray"
+    or
+    this = "Harriet" and result = "white"
+    or
+    this = "Mahala" and result = "black"
+    or
+    this = "Abby" and result = "red"
+    or
+    this = "Margaret" and result = "brown"
+    or
+    this = "Deb" and result = "brown"
+    or
+    this = "Minerva" and result = "brown"
+    or
+    this = "Severus" and result = "black"
+    or
+    this = "Lavina" and result = "brown"
+    or
+    this = "Adeline" and result = "brown"
+    or
+    this = "Cath" and result = "brown"
+    or
+    this = "Elisa" and result = "brown"
+    or
+    this = "Lucretia" and result = "gray"
+    or
+    this = "Anne" and result = "black"
+    or
+    this = "Eleanor" and result = "brown"
+    or
+    this = "Joanna" and result = "brown"
+    or
+    this = "Adam" and result = "black"
+    or
+    this = "Agnes" and result = "black"
+    or
+    this = "Rosanna" and result = "gray"
+    or
+    this = "Clara" and result = "blond"
+    or
+    this = "Melissa" and result = "brown"
+    or
+    this = "Amy" and result = "brown"
+    or
+    this = "Isabel" and result = "black"
+    or
+    this = "Jemima" and result = "red"
+    or
+    this = "Cordelia" and result = "red"
+    or
+    this = "Melinda" and result = "gray"
+    or
+    this = "Delila" and result = "white"
+    or
+    this = "Jeremiah" and result = "gray"
+    or
+    this = "Hester" and result = "black"
+    or
+    this = "Walter" and result = "black"
+    or
+    this = "Aaron" and result = "gray"
+    or
+    this = "Reuben" and result = "gray"
+    or
+    this = "Eli" and result = "gray"
+    or
+    this = "Amos" and result = "white"
+    or
+    this = "Augustus" and result = "white"
+    or
+    this = "Theodore" and result = "white"
+    or
+    this = "Timothy" and result = "brown"
+    or
+    this = "Cyrus" and result = "brown"
+    or
+    this = "Horace" and result = "brown"
+    or
+    this = "Simon" and result = "brown"
+    or
+    this = "Asa" and result = "brown"
+    or
+    this = "Frank" and result = "brown"
+    or
+    this = "Nelson" and result = "black"
+    or
+    this = "Leonard" and result = "black"
+    or
+    this = "Harrison" and result = "black"
+    or
+    this = "Anthony" and result = "black"
+    or
+    this = "Louis" and result = "black"
+    or
+    this = "Milton" and result = "blond"
+    or
+    this = "Noah" and result = "blond"
+    or
+    this = "Cornelius" and result = "red"
+    or
+    this = "Abdul" and result = "brown"
+    or
+    this = "Warren" and result = "red"
+    or
+    this = "Harvey" and result = "blond"
+    or
+    this = "Dennis" and result = "blond"
+    or
+    this = "Wesley" and result = "brown"
+    or
+    this = "Sylvester" and result = "brown"
+    or
+    this = "Gilbert" and result = "brown"
+    or
+    this = "Sullivan" and result = "brown"
+    or
+    this = "Edmund" and result = "brown"
+    or
+    this = "Wilson" and result = "blond"
+    or
+    this = "Perry" and result = "black"
+    or
+    this = "Simba" and result = "brown"
+    or
+    this = "Nala" and result = "brown"
+    or
+    this = "Rafiki" and result = "red"
+    or
+    this = "Shenzi" and result = "gray"
+    or
+    this = "Ernest" and result = "blond"
+    or
+    this = "Gertrude" and result = "brown"
+    or
+    this = "Oscar" and result = "blond"
+    or
+    this = "Lilian" and result = "brown"
+    or
+    this = "Raymond" and result = "brown"
+    or
+    this = "Elgar" and result = "brown"
+    or
+    this = "Elmer" and result = "brown"
+    or
+    this = "Herbert" and result = "brown"
+    or
+    this = "Maude" and result = "brown"
+    or
+    this = "Mae" and result = "brown"
+    or
+    this = "Otto" and result = "black"
+    or
+    this = "Edwin" and result = "black"
+    or
+    this = "Ophelia" and result = "brown"
+    or
+    this = "Parsley" and result = "brown"
+    or
+    this = "Sage" and result = "brown"
+    or
+    this = "Rosemary" and result = "brown"
+    or
+    this = "Thyme" and result = "brown"
+    or
+    this = "Garfunkel" and result = "brown"
+    or
+    this = "King Basil" and result = "brown"
+    or
+    this = "Stephen" and result = "black"
+    or
+    this = "Stephen" and result = "gray"
+  }
+
+  /** Gets the age of the person (in years). If the person is deceased, there is no result. */
+  int getAge() {
+    this = "Ronil" and result = 21
+    or
+    this = "Dina" and result = 53
+    or
+    this = "Ravi" and result = 16
+    or
+    this = "Bruce" and result = 35
+    or
+    this = "Jo" and result = 47
+    or
+    this = "Aida" and result = 26
+    or
+    this = "Esme" and result = 25
+    or
+    this = "Charlie" and result = 31
+    or
+    this = "Fred" and result = 68
+    or
+    this = "Meera" and result = 62
+    or
+    this = "Maya" and result = 29
+    or
+    this = "Chad" and result = 49
+    or
+    this = "Tiana" and result = 18
+    or
+    this = "Laura" and result = 2
+    or
+    this = "George" and result = 3
+    or
+    this = "Will" and result = 41
+    or
+    this = "Mary" and result = 51
+    or
+    this = "Almira" and result = 1
+    or
+    this = "Susannah" and result = 97
+    or
+    this = "Rhoda" and result = 39
+    or
+    this = "Cynthia" and result = 89
+    or
+    this = "Eunice" and result = 83
+    or
+    this = "Olive" and result = 25
+    or
+    this = "Virginia" and result = 52
+    or
+    this = "Angeline" and result = 22
+    or
+    this = "Helen" and result = 79
+    or
+    this = "Cornelia" and result = 59
+    or
+    this = "Harriet" and result = 57
+    or
+    this = "Mahala" and result = 61
+    or
+    this = "Abby" and result = 24
+    or
+    this = "Margaret" and result = 59
+    or
+    this = "Deb" and result = 31
+    or
+    this = "Minerva" and result = 72
+    or
+    this = "Severus" and result = 61
+    or
+    this = "Lavina" and result = 33
+    or
+    this = "Adeline" and result = 17
+    or
+    this = "Cath" and result = 22
+    or
+    this = "Elisa" and result = 9
+    or
+    this = "Lucretia" and result = 56
+    or
+    this = "Anne" and result = 11
+    or
+    this = "Eleanor" and result = 80
+    or
+    this = "Joanna" and result = 43
+    or
+    this = "Adam" and result = 37
+    or
+    this = "Agnes" and result = 47
+    or
+    this = "Rosanna" and result = 61
+    or
+    this = "Clara" and result = 31
+    or
+    this = "Melissa" and result = 37
+    or
+    this = "Amy" and result = 12
+    or
+    this = "Isabel" and result = 6
+    or
+    this = "Jemima" and result = 16
+    or
+    this = "Cordelia" and result = 21
+    or
+    this = "Melinda" and result = 55
+    or
+    this = "Delila" and result = 66
+    or
+    this = "Jeremiah" and result = 54
+    or
+    this = "Elijah" and result = 42
+    or
+    this = "Hester" and result = 68
+    or
+    this = "Walter" and result = 66
+    or
+    this = "Oliver" and result = 33
+    or
+    this = "Hugh" and result = 51
+    or
+    this = "Aaron" and result = 49
+    or
+    this = "Reuben" and result = 58
+    or
+    this = "Eli" and result = 70
+    or
+    this = "Amos" and result = 65
+    or
+    this = "Augustus" and result = 56
+    or
+    this = "Theodore" and result = 69
+    or
+    this = "Ira" and result = 1
+    or
+    this = "Timothy" and result = 54
+    or
+    this = "Cyrus" and result = 78
+    or
+    this = "Horace" and result = 34
+    or
+    this = "Simon" and result = 23
+    or
+    this = "Asa" and result = 28
+    or
+    this = "Frank" and result = 59
+    or
+    this = "Nelson" and result = 38
+    or
+    this = "Leonard" and result = 58
+    or
+    this = "Harrison" and result = 7
+    or
+    this = "Anthony" and result = 2
+    or
+    this = "Louis" and result = 34
+    or
+    this = "Milton" and result = 36
+    or
+    this = "Noah" and result = 48
+    or
+    this = "Cornelius" and result = 41
+    or
+    this = "Abdul" and result = 67
+    or
+    this = "Warren" and result = 47
+    or
+    this = "Harvey" and result = 31
+    or
+    this = "Dennis" and result = 39
+    or
+    this = "Wesley" and result = 13
+    or
+    this = "Sylvester" and result = 19
+    or
+    this = "Gilbert" and result = 16
+    or
+    this = "Sullivan" and result = 17
+    or
+    this = "Edmund" and result = 29
+    or
+    this = "Wilson" and result = 27
+    or
+    this = "Perry" and result = 31
+    or
+    this = "Matthew" and result = 55
+    or
+    this = "Simba" and result = 8
+    or
+    this = "Nala" and result = 7
+    or
+    this = "Rafiki" and result = 76
+    or
+    this = "Shenzi" and result = 67
+  }
+
+  /** Gets the height of the person (in cm). If the person is deceased, there is no result. */
+  float getHeight() {
+    this = "Ronil" and result = 183.0
+    or
+    this = "Dina" and result = 155.1
+    or
+    this = "Ravi" and result = 175.2
+    or
+    this = "Bruce" and result = 191.3
+    or
+    this = "Jo" and result = 163.4
+    or
+    this = "Aida" and result = 182.6
+    or
+    this = "Esme" and result = 176.9
+    or
+    this = "Charlie" and result = 189.7
+    or
+    this = "Fred" and result = 179.4
+    or
+    this = "Meera" and result = 160.1
+    or
+    this = "Maya" and result = 153.0
+    or
+    this = "Chad" and result = 168.5
+    or
+    this = "Tiana" and result = 149.7
+    or
+    this = "Laura" and result = 87.5
+    or
+    this = "George" and result = 96.4
+    or
+    this = "Will" and result = 167.1
+    or
+    this = "Mary" and result = 159.8
+    or
+    this = "Almira" and result = 62.1
+    or
+    this = "Susannah" and result = 145.8
+    or
+    this = "Rhoda" and result = 180.1
+    or
+    this = "Cynthia" and result = 161.8
+    or
+    this = "Eunice" and result = 153.2
+    or
+    this = "Olive" and result = 179.9
+    or
+    this = "Virginia" and result = 165.1
+    or
+    this = "Angeline" and result = 172.3
+    or
+    this = "Helen" and result = 163.1
+    or
+    this = "Cornelia" and result = 160.8
+    or
+    this = "Harriet" and result = 163.2
+    or
+    this = "Mahala" and result = 157.7
+    or
+    this = "Abby" and result = 174.5
+    or
+    this = "Margaret" and result = 165.6
+    or
+    this = "Deb" and result = 171.6
+    or
+    this = "Minerva" and result = 168.7
+    or
+    this = "Severus" and result = 188.8
+    or
+    this = "Lavina" and result = 155.1
+    or
+    this = "Adeline" and result = 165.5
+    or
+    this = "Cath" and result = 147.8
+    or
+    this = "Elisa" and result = 129.4
+    or
+    this = "Lucretia" and result = 153.6
+    or
+    this = "Anne" and result = 140.4
+    or
+    this = "Eleanor" and result = 151.1
+    or
+    this = "Joanna" and result = 167.2
+    or
+    this = "Adam" and result = 155.5
+    or
+    this = "Agnes" and result = 156.8
+    or
+    this = "Rosanna" and result = 162.4
+    or
+    this = "Clara" and result = 158.6
+    or
+    this = "Melissa" and result = 182.3
+    or
+    this = "Amy" and result = 147.1
+    or
+    this = "Isabel" and result = 121.4
+    or
+    this = "Jemima" and result = 149.8
+    or
+    this = "Cordelia" and result = 151.7
+    or
+    this = "Melinda" and result = 154.4
+    or
+    this = "Delila" and result = 163.4
+    or
+    this = "Jeremiah" and result = 167.5
+    or
+    this = "Elijah" and result = 184.5
+    or
+    this = "Hester" and result = 152.7
+    or
+    this = "Walter" and result = 159.6
+    or
+    this = "Oliver" and result = 192.4
+    or
+    this = "Hugh" and result = 173.1
+    or
+    this = "Aaron" and result = 176.6
+    or
+    this = "Reuben" and result = 169.9
+    or
+    this = "Eli" and result = 180.4
+    or
+    this = "Amos" and result = 167.4
+    or
+    this = "Augustus" and result = 156.5
+    or
+    this = "Theodore" and result = 176.6
+    or
+    this = "Ira" and result = 54.1
+    or
+    this = "Timothy" and result = 172.2
+    or
+    this = "Cyrus" and result = 157.9
+    or
+    this = "Horace" and result = 169.3
+    or
+    this = "Simon" and result = 157.1
+    or
+    this = "Asa" and result = 149.4
+    or
+    this = "Frank" and result = 167.2
+    or
+    this = "Nelson" and result = 173.0
+    or
+    this = "Leonard" and result = 172.0
+    or
+    this = "Harrison" and result = 126.0
+    or
+    this = "Anthony" and result = 98.4
+    or
+    this = "Louis" and result = 186.8
+    or
+    this = "Milton" and result = 157.8
+    or
+    this = "Noah" and result = 190.5
+    or
+    this = "Cornelius" and result = 183.1
+    or
+    this = "Abdul" and result = 182.0
+    or
+    this = "Warren" and result = 175.0
+    or
+    this = "Harvey" and result = 169.3
+    or
+    this = "Dennis" and result = 160.4
+    or
+    this = "Wesley" and result = 139.8
+    or
+    this = "Sylvester" and result = 188.2
+    or
+    this = "Gilbert" and result = 177.6
+    or
+    this = "Sullivan" and result = 168.3
+    or
+    this = "Edmund" and result = 159.2
+    or
+    this = "Wilson" and result = 167.6
+    or
+    this = "Perry" and result = 189.1
+    or
+    this = "Matthew" and result = 167.2
+    or
+    this = "Simba" and result = 140.1
+    or
+    this = "Nala" and result = 138.0
+    or
+    this = "Rafiki" and result = 139.3
+    or
+    this = "Shenzi" and result = 171.1
+  }
+
+  /** Gets the location of the person's home ("north", "south", "east", or "west"). If the person is deceased, there is no result. */
+  string getLocation() {
+    this = "Ronil" and result = "north"
+    or
+    this = "Dina" and result = "north"
+    or
+    this = "Ravi" and result = "north"
+    or
+    this = "Bruce" and result = "south"
+    or
+    this = "Jo" and result = "west"
+    or
+    this = "Aida" and result = "east"
+    or
+    this = "Esme" and result = "east"
+    or
+    this = "Charlie" and result = "south"
+    or
+    this = "Fred" and result = "west"
+    or
+    this = "Meera" and result = "south"
+    or
+    this = "Maya" and result = "south"
+    or
+    this = "Chad" and result = "south"
+    or
+    this = "Tiana" and result = "west"
+    or
+    this = "Laura" and result = "south"
+    or
+    this = "George" and result = "south"
+    or
+    this = "Will" and result = "south"
+    or
+    this = "Mary" and result = "south"
+    or
+    this = "Almira" and result = "south"
+    or
+    this = "Susannah" and result = "north"
+    or
+    this = "Rhoda" and result = "north"
+    or
+    this = "Cynthia" and result = "north"
+    or
+    this = "Eunice" and result = "north"
+    or
+    this = "Olive" and result = "west"
+    or
+    this = "Virginia" and result = "west"
+    or
+    this = "Angeline" and result = "west"
+    or
+    this = "Helen" and result = "west"
+    or
+    this = "Cornelia" and result = "east"
+    or
+    this = "Harriet" and result = "east"
+    or
+    this = "Mahala" and result = "east"
+    or
+    this = "Abby" and result = "east"
+    or
+    this = "Margaret" and result = "east"
+    or
+    this = "Deb" and result = "east"
+    or
+    this = "Minerva" and result = "south"
+    or
+    this = "Severus" and result = "north"
+    or
+    this = "Lavina" and result = "east"
+    or
+    this = "Adeline" and result = "west"
+    or
+    this = "Cath" and result = "east"
+    or
+    this = "Elisa" and result = "east"
+    or
+    this = "Lucretia" and result = "north"
+    or
+    this = "Anne" and result = "north"
+    or
+    this = "Eleanor" and result = "south"
+    or
+    this = "Joanna" and result = "south"
+    or
+    this = "Adam" and result = "east"
+    or
+    this = "Agnes" and result = "east"
+    or
+    this = "Rosanna" and result = "east"
+    or
+    this = "Clara" and result = "east"
+    or
+    this = "Melissa" and result = "west"
+    or
+    this = "Amy" and result = "west"
+    or
+    this = "Isabel" and result = "west"
+    or
+    this = "Jemima" and result = "west"
+    or
+    this = "Cordelia" and result = "west"
+    or
+    this = "Melinda" and result = "west"
+    or
+    this = "Delila" and result = "south"
+    or
+    this = "Jeremiah" and result = "north"
+    or
+    this = "Elijah" and result = "north"
+    or
+    this = "Hester" and result = "east"
+    or
+    this = "Walter" and result = "east"
+    or
+    this = "Oliver" and result = "east"
+    or
+    this = "Hugh" and result = "south"
+    or
+    this = "Aaron" and result = "south"
+    or
+    this = "Reuben" and result = "west"
+    or
+    this = "Eli" and result = "west"
+    or
+    this = "Amos" and result = "east"
+    or
+    this = "Augustus" and result = "south"
+    or
+    this = "Theodore" and result = "west"
+    or
+    this = "Ira" and result = "south"
+    or
+    this = "Timothy" and result = "north"
+    or
+    this = "Cyrus" and result = "north"
+    or
+    this = "Horace" and result = "east"
+    or
+    this = "Simon" and result = "east"
+    or
+    this = "Asa" and result = "east"
+    or
+    this = "Frank" and result = "west"
+    or
+    this = "Nelson" and result = "west"
+    or
+    this = "Leonard" and result = "west"
+    or
+    this = "Harrison" and result = "north"
+    or
+    this = "Anthony" and result = "north"
+    or
+    this = "Louis" and result = "north"
+    or
+    this = "Milton" and result = "south"
+    or
+    this = "Noah" and result = "south"
+    or
+    this = "Cornelius" and result = "east"
+    or
+    this = "Abdul" and result = "east"
+    or
+    this = "Warren" and result = "west"
+    or
+    this = "Harvey" and result = "west"
+    or
+    this = "Dennis" and result = "west"
+    or
+    this = "Wesley" and result = "west"
+    or
+    this = "Sylvester" and result = "south"
+    or
+    this = "Gilbert" and result = "east"
+    or
+    this = "Sullivan" and result = "east"
+    or
+    this = "Edmund" and result = "north"
+    or
+    this = "Wilson" and result = "north"
+    or
+    this = "Perry" and result = "west"
+    or
+    this = "Matthew" and result = "east"
+    or
+    this = "Simba" and result = "south"
+    or
+    this = "Nala" and result = "south"
+    or
+    this = "Rafiki" and result = "north"
+    or
+    this = "Shenzi" and result = "west"
+  }
+
+  /** Holds if the person is deceased. */
+  predicate isDeceased() {
+    this = "Ernest" or
+    this = "Gertrude" or
+    this = "Oscar" or
+    this = "Lilian" or
+    this = "Edwin" or
+    this = "Raymond" or
+    this = "Elgar" or
+    this = "Elmer" or
+    this = "Herbert" or
+    this = "Maude" or
+    this = "Mae" or
+    this = "Otto" or
+    this = "Ophelia" or
+    this = "Parsley" or
+    this = "Sage" or
+    this = "Rosemary" or
+    this = "Thyme" or
+    this = "Garfunkel" or
+    this = "King Basil"
+  }
+
+  /** Gets a parent of the person (alive or deceased). */
+  Person getAParent() {
+    this = "Stephen" and result = "Edmund"
+    or
+    this = "Edmund" and result = "Augustus"
+    or
+    this = "Augustus" and result = "Stephen"
+    or
+    this = "Abby" and result = "Cornelia"
+    or
+    this = "Abby" and result = "Amos"
+    or
+    this = "Abdul" and result = "Susannah"
+    or
+    this = "Adam" and result = "Amos"
+    or
+    this = "Adeline" and result = "Melinda"
+    or
+    this = "Adeline" and result = "Frank"
+    or
+    this = "Agnes" and result = "Abdul"
+    or
+    this = "Aida" and result = "Agnes"
+    or
+    this = "Almira" and result = "Sylvester"
+    or
+    this = "Amos" and result = "Eunice"
+    or
+    this = "Amy" and result = "Noah"
+    or
+    this = "Amy" and result = "Chad"
+    or
+    this = "Angeline" and result = "Reuben"
+    or
+    this = "Angeline" and result = "Lucretia"
+    or
+    this = "Anne" and result = "Rhoda"
+    or
+    this = "Anne" and result = "Louis"
+    or
+    this = "Anthony" and result = "Lavina"
+    or
+    this = "Anthony" and result = "Asa"
+    or
+    this = "Asa" and result = "Cornelia"
+    or
+    this = "Cath" and result = "Harriet"
+    or
+    this = "Charlie" and result = "Matthew"
+    or
+    this = "Clara" and result = "Ernest"
+    or
+    this = "Cornelia" and result = "Cynthia"
+    or
+    this = "Cornelius" and result = "Eli"
+    or
+    this = "Deb" and result = "Margaret"
+    or
+    this = "Dennis" and result = "Fred"
+    or
+    this = "Eli" and result = "Susannah"
+    or
+    this = "Elijah" and result = "Delila"
+    or
+    this = "Elisa" and result = "Deb"
+    or
+    this = "Elisa" and result = "Horace"
+    or
+    this = "Esme" and result = "Margaret"
+    or
+    this = "Frank" and result = "Eleanor"
+    or
+    this = "Frank" and result = "Cyrus"
+    or
+    this = "George" and result = "Maya"
+    or
+    this = "George" and result = "Wilson"
+    or
+    this = "Gilbert" and result = "Cornelius"
+    or
+    this = "Harriet" and result = "Cynthia"
+    or
+    this = "Harrison" and result = "Louis"
+    or
+    this = "Harvey" and result = "Fred"
+    or
+    this = "Helen" and result = "Susannah"
+    or
+    this = "Hester" and result = "Edwin"
+    or
+    this = "Hugh" and result = "Cyrus"
+    or
+    this = "Hugh" and result = "Helen"
+    or
+    this = "Ira" and result = "Maya"
+    or
+    this = "Ira" and result = "Wilson"
+    or
+    this = "Isabel" and result = "Perry"
+    or
+    this = "Isabel" and result = "Harvey"
+    or
+    this = "Jemima" and result = "Melinda"
+    or
+    this = "Jemima" and result = "Frank"
+    or
+    this = "Ernest" and result = "Lilian"
+    or
+    this = "Ernest" and result = "Oscar"
+    or
+    this = "Gertrude" and result = "Ophelia"
+    or
+    this = "Gertrude" and result = "Raymond"
+    or
+    this = "Lilian" and result = "Elgar"
+    or
+    this = "Lilian" and result = "Mae"
+    or
+    this = "Raymond" and result = "Elgar"
+    or
+    this = "Raymond" and result = "Mae"
+    or
+    this = "Elmer" and result = "Ophelia"
+    or
+    this = "Elmer" and result = "Raymond"
+    or
+    this = "Herbert" and result = "Ophelia"
+    or
+    this = "Herbert" and result = "Raymond"
+    or
+    this = "Maude" and result = "Ophelia"
+    or
+    this = "Maude" and result = "Raymond"
+    or
+    this = "Otto" and result = "Elgar"
+    or
+    this = "Otto" and result = "Mae"
+    or
+    this = "Edwin" and result = "Otto"
+    or
+    this = "Parsley" and result = "Simon"
+    or
+    this = "Parsley" and result = "Garfunkel"
+    or
+    this = "Sage" and result = "Simon"
+    or
+    this = "Sage" and result = "Garfunkel"
+    or
+    this = "Rosemary" and result = "Simon"
+    or
+    this = "Rosemary" and result = "Garfunkel"
+    or
+    this = "Thyme" and result = "Simon"
+    or
+    this = "Thyme" and result = "Garfunkel"
+    or
+    this = "King Basil" and result = "Ophelia"
+    or
+    this = "King Basil" and result = "Raymond"
+    or
+    this = "Jo" and result = "Theodore"
+    or
+    this = "Joanna" and result = "Shenzi"
+    or
+    this = "Laura" and result = "Maya"
+    or
+    this = "Laura" and result = "Wilson"
+    or
+    this = "Lavina" and result = "Mahala"
+    or
+    this = "Lavina" and result = "Walter"
+    or
+    this = "Leonard" and result = "Cyrus"
+    or
+    this = "Leonard" and result = "Helen"
+    or
+    this = "Lucretia" and result = "Eleanor"
+    or
+    this = "Lucretia" and result = "Cyrus"
+    or
+    this = "Mahala" and result = "Eunice"
+    or
+    this = "Margaret" and result = "Cynthia"
+    or
+    this = "Matthew" and result = "Cyrus"
+    or
+    this = "Matthew" and result = "Helen"
+    or
+    this = "Maya" and result = "Meera"
+    or
+    this = "Melinda" and result = "Rafiki"
+    or
+    this = "Melissa" and result = "Mahala"
+    or
+    this = "Melissa" and result = "Walter"
+    or
+    this = "Nala" and result = "Bruce"
+    or
+    this = "Nelson" and result = "Mahala"
+    or
+    this = "Nelson" and result = "Walter"
+    or
+    this = "Noah" and result = "Eli"
+    or
+    this = "Olive" and result = "Reuben"
+    or
+    this = "Olive" and result = "Lucretia"
+    or
+    this = "Oliver" and result = "Matthew"
+    or
+    this = "Perry" and result = "Leonard"
+    or
+    this = "Ravi" and result = "Dina"
+    or
+    this = "Simba" and result = "Will"
+    or
+    this = "Simon" and result = "Margaret"
+    or
+    this = "Sullivan" and result = "Cornelius"
+    or
+    this = "Sylvester" and result = "Timothy"
+    or
+    this = "Theodore" and result = "Susannah"
+    or
+    this = "Tiana" and result = "Jo"
+    or
+    this = "Virginia" and result = "Helen"
+    or
+    this = "Warren" and result = "Shenzi"
+    or
+    this = "Wesley" and result = "Warren"
+    or
+    this = "Wesley" and result = "Jo"
+    or
+    this = "Will" and result = "Eli"
+  }
+
+  /** Holds if the person is allowed in the region. Initially, all villagers are allowed in every region. */
+  predicate isAllowedIn(string region) {
+    region = "north" or
+    region = "south" or
+    region = "east" or
+    region = "west"
+  }
+}
+
+/** Returns a parent of the person. */
+Person parentOf(Person p) { result = p.getAParent() }