diff --git a/osc/main.py b/osc/main.py
index 21b23c5..8a7b0ba 100644
--- a/osc/main.py
+++ b/osc/main.py
@@ -2,7 +2,7 @@ from graphviz import Digraph
 from pythonosc.dispatcher import Dispatcher
 from pythonosc.osc_server import BlockingOSCUDPServer
 
-g = Digraph('G', filename='graph.gv', format='png')
+g = Digraph('G', filename='graph.gv', format='pdf')
 
 # last vertex received
 v = -1
@@ -14,6 +14,10 @@ t = ""
 def print_vertex(address, *args):
     global v
     v = args[args.index('vertex') + 1]
+    if v == -1:
+        return
+    g.node(str(v))
+    g.render("Test")
     print(v)
 
 def print_edge(address, *args):
@@ -23,6 +27,10 @@ def print_edge(address, *args):
     w = args[args.index('w') + 1]
     t = args[args.index('edge_type') + 1]
     print((v,w,t))
+    if v == -1 or w == -1:
+        return
+    g.edge(str(v), str(w))
+    g.render("Test")
 
 dispatcher = Dispatcher()
 dispatcher.map("/edge", print_edge)