diff --git a/BUGS.md b/BUGS.md
index 8f885b5..dd8456d 100644
--- a/BUGS.md
+++ b/BUGS.md
@@ -1,6 +1,6 @@
 BUGS:
 
-- servir ficheiros de public temporariamente
+- load/save the knowledge state of the student
 - se students.db não existe, rebenta.
 - database hardcoded in LearnApp.
 - implementar xsrf. Ver [http://www.tornadoweb.org/en/stable/guide/security.html#cross-site-request-forgery-protection]()
@@ -14,6 +14,7 @@ TODO:
 
 SOLVED:
 
+- servir ficheiros de public temporariamente
 - path dos generators scripts mal construido
 - questions hardcoded in LearnApp.
 - Factory para cada pergunta individual em vez de pool
diff --git a/app.py b/app.py
index 6582b2b..7930ecb 100644
--- a/app.py
+++ b/app.py
@@ -74,6 +74,12 @@ class LearnApp(object):
         return self.online[uid].get('name', '')
 
     # ------------------------------------------------------------------------
+    def get_current_public_dir(self, uid):
+        topic = self.online[uid]['state'].topic
+        p = self.depgraph.graph['path']
+        return path.join(p, topic, 'public')
+
+    # ------------------------------------------------------------------------
     # check answer and if correct returns new question, otherise returns None
     def check_answer(self, uid, answer):
         logger.debug(f'check_answer("{uid}", "{answer}")')
diff --git a/knowledge.py b/knowledge.py
index c5b340b..d3ffa15 100644
--- a/knowledge.py
+++ b/knowledge.py
@@ -21,7 +21,8 @@ class Knowledge(object):
         self.state = state   # {node: level, node: level, ...}
         self.current_question = None
 
-        # self.seq = nx.topological_sort(self.depgraph)
+        self.seq = nx.topological_sort(self.depgraph)
+        self.topic = None
 
     def get_current_question(self):
         return self.current_question
@@ -36,10 +37,10 @@ class Knowledge(object):
             g = self.depgraph
             # choose topic, ie, node of the graph
             # print(g.nodes())
-            topic = random.choice(g.nodes())  # FIXME
+            self.topic = random.choice(g.nodes())  # FIXME
             # print(topic)
             # choose question from that topic
-            question = random.choice(g.node[topic]['factory'])
+            question = random.choice(g.node[self.topic]['factory'])
             # print(question)
 
             self.current_question = question.generate()
diff --git a/serve.py b/serve.py
index fb4a429..e9f8a5a 100755
--- a/serve.py
+++ b/serve.py
@@ -34,10 +34,11 @@ from tools import load_yaml, md
 class WebApplication(tornado.web.Application):
     def __init__(self):
         handlers = [
-            (r'/',          LearnHandler),
             (r'/login',     LoginHandler),
             (r'/logout',    LogoutHandler),
             (r'/question',  QuestionHandler),
+            (r'/',          LearnHandler),
+            (r'/(.+)',      FileHandler),
         ]
         settings = {
             'template_path': os.path.join(os.path.dirname(__file__), 'templates'),
@@ -112,6 +113,18 @@ class LearnHandler(BaseHandler):
             )
 
 # ----------------------------------------------------------------------------
+class FileHandler(BaseHandler):
+    @tornado.web.authenticated
+    def get(self, filename):
+        uid = self.current_user
+        public_dir = self.learn.get_current_public_dir(uid)
+        try:
+            with open(os.path.join(public_dir, filename), 'rb') as f:
+                self.write(f.read())
+        except FileNotFoundError:
+            raise tornado.web.HTTPError(404)
+
+# ----------------------------------------------------------------------------
 # respond to AJAX to get a JSON question
 class QuestionHandler(BaseHandler):
     templates = {
diff --git a/static/css/learn.css b/static/css/learn.css
index bf90bc7..b54aac6 100644
--- a/static/css/learn.css
+++ b/static/css/learn.css
@@ -1,3 +1,9 @@
-body { 
-    padding-top: 65px; 
+body {
+    padding-top: 65px;
+}
+
+img {
+    display: block;
+    margin:  auto;
+    width: 80%;
 }
\ No newline at end of file
--
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