5 files changed, 15 insertions, 10 deletions
diff --git a/prolog/problems/family_relations/grandparent_2/common.py b/prolog/problems/family_relations/grandparent_2/common.py
index 98e40fc..8ccd23d 100644
--- a/prolog/problems/family_relations/grandparent_2/common.py
+++ b/prolog/problems/family_relations/grandparent_2/common.py
@@ -103,16 +103,21 @@ def hint(program, solved_problems):
             'grandparent(X, _), \+ parent(X, _)'):
             return [{'id': 'x_must_be_parent'}]
 
-        # X does not necessarily need to have a parent
-        if prolog.engine.ask_one(engine_id,
-            'grandparent(X, _), \+ parent(_, X)') == 'false':
-            return [{'id': 'x_need_not_have_parent'}]
-
         # Y must have a parent
         if prolog.engine.ask_truth(engine_id,
             'grandparent(_, Y), \+ parent(_, Y)'):
             return [{'id': 'y_must_have_parent'}]
 
+        # stop further hint testing if target predicate is always true or always false
+        if prolog.engine.ask_truth(engine_id,
+            '\+ grandparent(_, _) ; findall(X/Y, grandparent(X, Y), [A/B]), var(A), var(B)'):
+            return []
+
+        # X does not necessarily need to have a parent
+        if prolog.engine.ask_one(engine_id,
+            'grandparent(X, _), \+ parent(_, X)') == 'false':
+            return [{'id': 'x_need_not_have_parent'}]
+
         # Y does not necessarily need to be a parent
         if prolog.engine.ask_one(engine_id,
             'grandparent(_, Y), \+ parent(Y, _)') == 'false':
@@ -125,5 +130,5 @@ def hint(program, solved_problems):
         if engine_id:
             prolog.engine.destroy(engine_id)
 
-    return None
+    return []
 
diff --git a/prolog/problems/family_relations/mother_2/Mother-1.png b/prolog/problems/family_relations/mother_2/Mother-1.png
new file mode 100644
index 0000000..239b54f
--- /dev/null
+++ b/prolog/problems/family_relations/mother_2/Mother-1.png
diff --git a/prolog/problems/family_relations/mother_2/Mother-2.png b/prolog/problems/family_relations/mother_2/Mother-2.png
new file mode 100644
index 0000000..e0179e4
--- /dev/null
+++ b/prolog/problems/family_relations/mother_2/Mother-2.png
diff --git a/prolog/problems/family_relations/mother_2/Mother-3.png b/prolog/problems/family_relations/mother_2/Mother-3.png
new file mode 100644
index 0000000..e0ea5c1
--- /dev/null
+++ b/prolog/problems/family_relations/mother_2/Mother-3.png
diff --git a/prolog/problems/family_relations/mother_2/sl.py b/prolog/problems/family_relations/mother_2/sl.py
index 3494096..bd4d57e 100644
--- a/prolog/problems/family_relations/mother_2/sl.py
+++ b/prolog/problems/family_relations/mother_2/sl.py
@@ -16,10 +16,10 @@ description = '''\
 
 plan = [
     '''\
-<p><img src="Mother-1.png" /></p>
+<p><img src="[%@resource Mother-1.png%]" alt="Mama ima otroka in je ženskega spola." /></p>
 <p>Loni naj zbriše imena relacij (parent, mother) s te slike!</p>''',
     '''\
-<p><img src="Mother-1.png" /></p>''',
+<p><img src="[%@resource Mother-1.png%]" alt="Mama X je starš od Y in je ženskega spola." /></p>''',
     '''\
 <p>Če je <code>X</code> ženska in je hkrati <code>X</code> starš od <code>Y</code>,
 potem je <code>X</code> mama od <code>Y</code>.</p>'''
@@ -32,12 +32,12 @@ hint = {
 
     'x_must_be_female': '''\
 <p>Mama je navadno ženskega spola.</p>
-<p><img src="Mother-2.png" /></p>
+<p><img src="[%@resource Mother-2.png%]" /></p>
 ''',
 
     'x_must_be_parent': '''\
 <p>Mama naj bi imela vsaj enega otroka... torej je starš od nekoga.</p>
-<p><img src="Mother-3.png" /></p>
+<p><img src="[%@resource Mother-3.png%]" /></p>
 ''',
 
     'y_can_be_of_any_gender': '''\