2 files changed, 25 insertions, 0 deletions
diff --git a/prolog/problems/family_relations/sister_2/common.py b/prolog/problems/family_relations/sister_2/common.py
new file mode 100644
index 0000000..75a2b62
--- /dev/null
+++ b/prolog/problems/family_relations/sister_2/common.py
@@ -0,0 +1,13 @@
+id = 96
+group = 'family_relations'
+number = 3
+visible = True
+facts = 'family_relations'
+
+solution = '''\
+sister(X, Y) :-
+  parent(P, X),
+  parent(P, Y),
+  female(X),
+  X \== Y.
+'''
diff --git a/prolog/problems/family_relations/sister_2/en.py b/prolog/problems/family_relations/sister_2/en.py
new file mode 100644
index 0000000..140b76f
--- /dev/null
+++ b/prolog/problems/family_relations/sister_2/en.py
@@ -0,0 +1,12 @@
+id = 96
+name = 'sister/2'
+slug = 'the sister relation'
+
+description = '''\
+<p><code>sister(X, Y)</code>: <code>X</code> is a sister of <code>Y</code>.</p>
+<pre>
+  ?- sister(vanessa, X).
+    X = patricia.
+</pre>'''
+
+hint = {}