diff --git a/specs/1.3/viz.rnc b/specs/1.3/viz.rnc
index fe9df10..fe9da08 100644
--- a/specs/1.3/viz.rnc
+++ b/specs/1.3/viz.rnc
@@ -65,15 +65,36 @@ thickness-type = [ a:defaultValue = "1.0" ]
 
 # Node shape
 node-shape-type =  [ a:defaultValue = "disc" ] 
-    string "disc" |
-    string "square" |
-    string "triangle" |
-    string "diamond" |
-    string "image"
+                        # Byte value in Gephi
+    string "disc"     | # 0000 0000 0
+    string "triangle" | # 0000 0001 1
+    string "square"   | # 0000 0010 2
+    string "diamond"  | # 0000 0011 3 
+    string "star"     | # 0000 0100 4
+    string "pentagon" | # 0000 0101 5 
+    string "hexagon"  | # 0000 0110 6
+    string "cross"    | # 0000 0111 7 
+    string "custom_1" | # 1000 0000 128
+    string "custom_2" | # 1000 0001 129
+    string "custom_3" | # 1000 0010 130
+    string "custom_4" | # 1000 0011 131
+    string "custom_5" | # 1000 0100 132
+    string "custom_6" | # 1000 0101 133
+    string "custom_7" | # 1000 0110 134
+    string "custom_8"   # 1000 0111 135
 
 # Edge shape
 edge-shape-type =  [ a:defaultValue = "solid" ] 
-    string "solid" |
-    string "dotted" |
-    string "dashed" |
-    string "double"
+                          # Byte value in Gephi
+    string "solid"    |   # 0000 0000 0
+    string "dotted"   |   # 0000 0001 1
+    string "dashed"   |   # 0000 0010 2
+    string "double"   |   # 0000 0011 3
+    string "custom_1" |   # 1000 0000 128
+    string "custom_2" |   # 1000 0001 129
+    string "custom_3" |   # 1000 0010 130
+    string "custom_4" |   # 1000 0011 131
+    string "custom_5" |   # 1000 0100 132
+    string "custom_6" |   # 1000 0101 133
+    string "custom_7" |   # 1000 0110 134
+    string "custom_8"     # 1000 0111 135
diff --git a/specs/1.3/viz.rng b/specs/1.3/viz.rng
index 5da3ea4..952ca80 100644
--- a/specs/1.3/viz.rng
+++ b/specs/1.3/viz.rng
@@ -147,19 +147,68 @@
   <define name="node-shape-type">
     <choice>
       <value type="string" datatypeLibrary="" a:defaultValue="disc">disc</value>
-      <value type="string" datatypeLibrary="">square</value>
+      <!-- Byte value in Gephi -->
+      <!-- 0000 0000 0 -->
       <value type="string" datatypeLibrary="">triangle</value>
+      <!-- 0000 0001 1 -->
+      <value type="string" datatypeLibrary="">square</value>
+      <!-- 0000 0010 2 -->
       <value type="string" datatypeLibrary="">diamond</value>
-      <value type="string" datatypeLibrary="">image</value>
+      <!-- 0000 0011 3 -->
+      <value type="string" datatypeLibrary="">star</value>
+      <!-- 0000 0100 4 -->
+      <value type="string" datatypeLibrary="">pentagon</value>
+      <!-- 0000 0101 5 -->
+      <value type="string" datatypeLibrary="">hexagon</value>
+      <!-- 0000 0110 6 -->
+      <value type="string" datatypeLibrary="">cross</value>
+      <!-- 0000 0111 7 -->
+      <value type="string" datatypeLibrary="">custom_1</value>
+      <!-- 1000 0000 128 -->
+      <value type="string" datatypeLibrary="">custom_2</value>
+      <!-- 1000 0001 129 -->
+      <value type="string" datatypeLibrary="">custom_3</value>
+      <!-- 1000 0010 130 -->
+      <value type="string" datatypeLibrary="">custom_4</value>
+      <!-- 1000 0011 131 -->
+      <value type="string" datatypeLibrary="">custom_5</value>
+      <!-- 1000 0100 132 -->
+      <value type="string" datatypeLibrary="">custom_6</value>
+      <!-- 1000 0101 133 -->
+      <value type="string" datatypeLibrary="">custom_7</value>
+      <!-- 1000 0110 134 -->
+      <value type="string" datatypeLibrary="">custom_8</value>
     </choice>
   </define>
+  <!-- 1000 0111 135 -->
   <!-- Edge shape -->
   <define name="edge-shape-type">
     <choice>
       <value type="string" datatypeLibrary="" a:defaultValue="solid">solid</value>
+      <!-- Byte value in Gephi -->
+      <!-- 0000 0000 0 -->
       <value type="string" datatypeLibrary="">dotted</value>
+      <!-- 0000 0001 1 -->
       <value type="string" datatypeLibrary="">dashed</value>
+      <!-- 0000 0010 2 -->
       <value type="string" datatypeLibrary="">double</value>
+      <!-- 0000 0011 3 -->
+      <value type="string" datatypeLibrary="">custom_1</value>
+      <!-- 1000 0000 128 -->
+      <value type="string" datatypeLibrary="">custom_2</value>
+      <!-- 1000 0001 129 -->
+      <value type="string" datatypeLibrary="">custom_3</value>
+      <!-- 1000 0010 130 -->
+      <value type="string" datatypeLibrary="">custom_4</value>
+      <!-- 1000 0011 131 -->
+      <value type="string" datatypeLibrary="">custom_5</value>
+      <!-- 1000 0100 132 -->
+      <value type="string" datatypeLibrary="">custom_6</value>
+      <!-- 1000 0101 133 -->
+      <value type="string" datatypeLibrary="">custom_7</value>
+      <!-- 1000 0110 134 -->
+      <value type="string" datatypeLibrary="">custom_8</value>
     </choice>
   </define>
 </grammar>
+<!-- 1000 0111 135 -->
diff --git a/specs/1.3/viz.xsd b/specs/1.3/viz.xsd
index 8a55d6f..57eff0e 100644
--- a/specs/1.3/viz.xsd
+++ b/specs/1.3/viz.xsd
@@ -63,12 +63,24 @@
   <xs:simpleType name="node-shape-type">
     <xs:restriction base="xs:string">
       <xs:enumeration value="disc"/>
-      <xs:enumeration value="square"/>
       <xs:enumeration value="triangle"/>
+      <xs:enumeration value="square"/>
       <xs:enumeration value="diamond"/>
-      <xs:enumeration value="image"/>
+      <xs:enumeration value="star"/>
+      <xs:enumeration value="pentagon"/>
+      <xs:enumeration value="hexagon"/>
+      <xs:enumeration value="cross"/>
+      <xs:enumeration value="custom_1"/>
+      <xs:enumeration value="custom_2"/>
+      <xs:enumeration value="custom_3"/>
+      <xs:enumeration value="custom_4"/>
+      <xs:enumeration value="custom_5"/>
+      <xs:enumeration value="custom_6"/>
+      <xs:enumeration value="custom_7"/>
+      <xs:enumeration value="custom_8"/>
     </xs:restriction>
   </xs:simpleType>
+  <!-- 1000 0111 135 -->
   <!-- Edge shape -->
   <xs:simpleType name="edge-shape-type">
     <xs:restriction base="xs:string">
@@ -76,6 +88,15 @@
       <xs:enumeration value="dotted"/>
       <xs:enumeration value="dashed"/>
       <xs:enumeration value="double"/>
+      <xs:enumeration value="custom_1"/>
+      <xs:enumeration value="custom_2"/>
+      <xs:enumeration value="custom_3"/>
+      <xs:enumeration value="custom_4"/>
+      <xs:enumeration value="custom_5"/>
+      <xs:enumeration value="custom_6"/>
+      <xs:enumeration value="custom_7"/>
+      <xs:enumeration value="custom_8"/>
     </xs:restriction>
   </xs:simpleType>
 </xs:schema>
+<!-- 1000 0111 135 -->