diff --git a/doc/devel/UML/iso_tree.violet b/doc/devel/UML/iso_tree.violet
index ac02a8d..9448c1b 100644
--- a/doc/devel/UML/iso_tree.violet
+++ b/doc/devel/UML/iso_tree.violet
@@ -23,8 +23,8 @@ biblio_file_id : char*</string>
    </object> 
    <object class="java.awt.geom.Point2D$Double"> 
     <void method="setLocation"> 
-     <double>830.9681801982362</double> 
-     <double>182.66718770734806</double> 
+     <double>1160.4799402311673</double> 
+     <double>240.649943764645</double> 
     </void> 
    </object> 
   </void> 
@@ -43,8 +43,8 @@ biblio_file_id : char*</string>
    </object> 
    <object class="java.awt.geom.Point2D$Double"> 
     <void method="setLocation"> 
-     <double>342.4798473529561</double> 
-     <double>272.1215741615781</double> 
+     <double>687.5479565719912</double> 
+     <double>269.2931470368318</double> 
     </void> 
    </object> 
   </void> 
@@ -65,8 +65,8 @@ hidden : enum</string>
    </object> 
    <object class="java.awt.geom.Point2D$Double"> 
     <void method="setLocation"> 
-     <double>451.0201548579207</double> 
-     <double>110.85108878154536</double> 
+     <double>706.83671056434</double> 
+     <double>108.4726745515399</double> 
     </void> 
    </object> 
   </void> 
@@ -87,8 +87,8 @@ children()</string>
    </object> 
    <object class="java.awt.geom.Point2D$Double"> 
     <void method="setLocation"> 
-     <double>643.4798473529561</double> 
-     <double>270.1215741615781</double> 
+     <double>986.1687535943008</double> 
+     <double>267.29314703683184</double> 
     </void> 
    </object> 
   </void> 
@@ -107,48 +107,92 @@ children()</string>
    </object> 
    <object class="java.awt.geom.Point2D$Double"> 
     <void method="setLocation"> 
-     <double>142.01551207221596</double> 
-     <double>273.3107812765808</double> 
+     <double>571.9364350336367</double> 
+     <double>273.31078127658077</double> 
     </void> 
    </object> 
   </void> 
   <void method="addNode"> 
    <object id="ClassNode5" class="com.horstmann.violet.ClassNode"> 
+    <void property="name"> 
+     <void property="text"> 
+      <string>Special</string> 
+     </void> 
+    </void> 
+   </object> 
+   <object class="java.awt.geom.Point2D$Double"> 
+    <void method="setLocation"> 
+     <double>813.0651280884073</double> 
+     <double>272.20749521231266</double> 
+    </void> 
+   </object> 
+  </void> 
+  <void method="addNode"> 
+   <object id="ClassNode6" class="com.horstmann.violet.ClassNode"> 
     <void property="attributes"> 
      <void property="text"> 
-      <string>block : uint32_t</string> 
+      <string>name : char*</string> 
+     </void> 
+    </void> 
+    <void property="methods"> 
+     <void property="text"> 
+      <string>&lt;&lt;static&gt;&gt;new(id)
+&lt;&lt;static&gt;&gt;read(src, opts)
+create()
+grow()</string> 
      </void> 
     </void> 
     <void property="name"> 
      <void property="text"> 
-      <string>PrevImgFile</string> 
+      <string>Image</string> 
      </void> 
     </void> 
    </object> 
    <object class="java.awt.geom.Point2D$Double"> 
     <void method="setLocation"> 
-     <double>397.8382435490256</double> 
-     <double>378.6685142175496</double> 
+     <double>1149.1980515339465</double> 
+     <double>455.5218613006981</double> 
     </void> 
    </object> 
   </void> 
   <void method="addNode"> 
-   <object id="ClassNode6" class="com.horstmann.violet.ClassNode"> 
-    <void property="attributes"> 
+   <object id="NoteNode0" class="com.horstmann.violet.NoteNode"> 
+    <void property="text"> 
      <void property="text"> 
-      <string>path : char *</string> 
+      <string>In addition to the dest as a path, it could
+be a good idea to have a ref to tree node.
+That way we can compute the dest on creation
+time, and thus links to files on image are also valid
+after moving or renaming those files</string> 
      </void> 
     </void> 
-    <void property="name"> 
+   </object> 
+   <object class="java.awt.geom.Point2D$Double"> 
+    <void method="setLocation"> 
+     <double>322.02220861890066</double> 
+     <double>362.2044136147912</double> 
+    </void> 
+   </object> 
+  </void> 
+  <void method="addNode"> 
+   <object id="NoteNode1" class="com.horstmann.violet.NoteNode"> 
+    <void property="text"> 
      <void property="text"> 
-      <string>LocalFile</string> 
+      <string>Image is a context for the creation of images. Its &quot;static&quot;
+methods, new() and read() are used to create a new
+image context, either from scratch or from an existing
+image (for example, a ms disc). The methods create() and
+grow() return an BurnSource suitable for libburn. 
+create() writes a full image, grow() only add to the image
+the new files, thus it is suitable for a new session
+</string> 
      </void> 
     </void> 
    </object> 
    <object class="java.awt.geom.Point2D$Double"> 
     <void method="setLocation"> 
-     <double>270.48382688356025</double> 
-     <double>384.9929640225687</double> 
+     <double>1234.6589462905451</double> 
+     <double>680.2741699796954</double> 
     </void> 
    </object> 
   </void> 
@@ -156,14 +200,14 @@ children()</string>
    <object id="ClassNode7" class="com.horstmann.violet.ClassNode"> 
     <void property="name"> 
      <void property="text"> 
-      <string>Special</string> 
+      <string>Ecma119Source</string> 
      </void> 
     </void> 
    </object> 
    <object class="java.awt.geom.Point2D$Double"> 
     <void method="setLocation"> 
-     <double>463.75437818225294</double> 
-     <double>273.6217087746859</double> 
+     <double>1423.5617211564486</double> 
+     <double>483.61244144432396</double> 
     </void> 
    </object> 
   </void> 
@@ -174,19 +218,19 @@ children()</string>
       <void property="name"> 
        <void property="text"> 
         <string>«interface»
-Filter</string> 
+BurnSource</string> 
        </void> 
       </void> 
      </object> 
     </void> 
     <void property="name"> 
-     <string>Filters</string> 
+     <string>Libburn</string> 
     </void> 
    </object> 
    <object class="java.awt.geom.Point2D$Double"> 
     <void method="setLocation"> 
-     <double>60.0</double> 
-     <double>340.0</double> 
+     <double>1420.0</double> 
+     <double>280.0</double> 
     </void> 
    </object> 
   </void> 
@@ -194,189 +238,327 @@ Filter</string>
    <object idref="InterfaceNode0"/> 
    <object class="java.awt.geom.Point2D$Double"> 
     <void method="setLocation"> 
-     <double>66.03818312655496</double> 
-     <double>371.74183342137127</double> 
+     <double>1431.4906533445824</double> 
+     <double>311.35760744838467</double> 
+    </void> 
+   </object> 
+  </void> 
+  <void method="addNode"> 
+   <object class="com.horstmann.violet.NoteNode"> 
+    <void property="text"> 
+     <void property="text"> 
+      <string>Class diagram for the public tree. Note that getters and setters are not shown,
+to improve readability. Note also that not all the attributes will have public getters
+or/and setters.
+El-Torito related information is shown in another diagram.
+We don&apos;t show the several functions in Dir to manage the tree.</string> 
+     </void> 
+    </void> 
+   </object> 
+   <object class="java.awt.geom.Point2D$Double"> 
+    <void method="setLocation"> 
+     <double>290.59037712396525</double> 
+     <double>9.859316379054512</double> 
     </void> 
    </object> 
   </void> 
   <void method="addNode"> 
    <object id="ClassNode8" class="com.horstmann.violet.ClassNode"> 
-    <void property="attributes"> 
+    <void property="name"> 
      <void property="text"> 
-      <string>name : char*</string> 
+      <string>FileSourceRegistry</string> 
      </void> 
     </void> 
-    <void property="methods"> 
+   </object> 
+   <object class="java.awt.geom.Point2D$Double"> 
+    <void method="setLocation"> 
+     <double>663.3494218736668</double> 
+     <double>707.2510088513307</double> 
+    </void> 
+   </object> 
+  </void> 
+  <void method="addNode"> 
+   <object id="NoteNode2" class="com.horstmann.violet.NoteNode"> 
+    <void property="text"> 
      <void property="text"> 
-      <string>&lt;&lt;static&gt;&gt;new(id)
-&lt;&lt;static&gt;&gt;read(src, opts)
-create()
-grow()</string> 
+      <string>A source that read its data from an arbitrary file
+descritor. size must be know in advance.</string> 
+     </void> 
+    </void> 
+   </object> 
+   <object class="java.awt.geom.Point2D$Double"> 
+    <void method="setLocation"> 
+     <double>888.4680374315352</double> 
+     <double>726.8792924010775</double> 
+    </void> 
+   </object> 
+  </void> 
+  <void method="addNode"> 
+   <object id="NoteNode3" class="com.horstmann.violet.NoteNode"> 
+    <void property="text"> 
+     <void property="text"> 
+      <string>The idea of the registry is to keep track
+of sources for the same file (to implement
+cache inodes, for exampe)</string> 
      </void> 
     </void> 
+   </object> 
+   <object class="java.awt.geom.Point2D$Double"> 
+    <void method="setLocation"> 
+     <double>796.4629867976516</double> 
+     <double>789.9797974644656</double> 
+    </void> 
+   </object> 
+  </void> 
+  <void method="addNode"> 
+   <object id="ClassNode9" class="com.horstmann.violet.ClassNode"> 
     <void property="name"> 
      <void property="text"> 
-      <string>Image</string> 
+      <string>TransformSource</string> 
      </void> 
     </void> 
    </object> 
    <object class="java.awt.geom.Point2D$Double"> 
     <void method="setLocation"> 
-     <double>829.5857864376269</double> 
-     <double>417.33809511662446</double> 
+     <double>465.9331463967205</double> 
+     <double>595.4414715712101</double> 
     </void> 
    </object> 
   </void> 
   <void method="addNode"> 
    <object id="InterfaceNode1" class="com.horstmann.violet.InterfaceNode"> 
+    <void property="methods"> 
+     <void property="text"> 
+      <string>get_size()
+read()
+open()
+close()
+is_repeatable()</string> 
+     </void> 
+    </void> 
     <void property="name"> 
      <void property="text"> 
       <string>«interface»
-DataSource</string> 
+FileSource</string> 
      </void> 
     </void> 
    </object> 
    <object class="java.awt.geom.Point2D$Double"> 
     <void method="setLocation"> 
-     <double>639.1500915071317</double> 
-     <double>437.7684840063146</double> 
+     <double>685.9331463967205</double> 
+     <double>410.4414715712108</double> 
     </void> 
    </object> 
   </void> 
   <void method="addNode"> 
-   <object id="NoteNode0" class="com.horstmann.violet.NoteNode"> 
+   <object id="NoteNode4" class="com.horstmann.violet.NoteNode"> 
     <void property="text"> 
      <void property="text"> 
-      <string>In addition to the dest as a path, it could
-be a good idea to have a ref to tree node.
-That way we can compute the dest on creation
-time, and thus links to files on image are also valid
-after moving or renaming those files</string> 
+      <string>A Filter do a tranformation on a stream of data.
+The main difference with TransformSources is that
+a Filter can be applied to several sources.
+NOTES: 
+- filter() method still to define
+- A filter_changes_size() method can be useful
+</string> 
      </void> 
     </void> 
    </object> 
    <object class="java.awt.geom.Point2D$Double"> 
     <void method="setLocation"> 
-     <double>16.152744527534395</double> 
-     <double>121.33809511662423</double> 
+     <double>350.5947306335493</double> 
+     <double>803.951562474507</double> 
     </void> 
    </object> 
   </void> 
   <void method="addNode"> 
-   <object id="NoteNode1" class="com.horstmann.violet.NoteNode"> 
-    <void property="text"> 
+   <object id="InterfaceNode2" class="com.horstmann.violet.InterfaceNode"> 
+    <void property="methods"> 
      <void property="text"> 
-      <string>Image is a context for the creation of images. Its &quot;static&quot;
-methods, new() and read() are used to create a new
-image context, either from scratch or from an existing
-image (for example, a ms disc). The methods create() and
-grow() return an BurnSource suitable for libburn. 
-create() writes a full image, grow() only add to the image
-the new files, thus it is suitable for a new session
-</string> 
+      <string>filter(in, out)</string> 
+     </void> 
+    </void> 
+    <void property="name"> 
+     <void property="text"> 
+      <string>«interface»
+Filter</string> 
      </void> 
     </void> 
    </object> 
    <object class="java.awt.geom.Point2D$Double"> 
     <void method="setLocation"> 
-     <double>988.5857864376269</double> 
-     <double>547.3380951166246</double> 
+     <double>274.0746933916357</double> 
+     <double>694.5765090198104</double> 
     </void> 
    </object> 
   </void> 
   <void method="addNode"> 
-   <object id="ClassNode9" class="com.horstmann.violet.ClassNode"> 
+   <object id="ClassNode10" class="com.horstmann.violet.ClassNode"> 
+    <void property="attributes"> 
+     <void property="text"> 
+      <string>size : off_t
+block : uint32_t</string> 
+     </void> 
+    </void> 
     <void property="name"> 
      <void property="text"> 
-      <string>Ecma119Source</string> 
+      <string>PreviousImageSource</string> 
+     </void> 
+    </void> 
+   </object> 
+   <object class="java.awt.geom.Point2D$Double"> 
+    <void method="setLocation"> 
+     <double>976.3688193543292</double> 
+     <double>599.7669830819689</double> 
+    </void> 
+   </object> 
+  </void> 
+  <void method="addNode"> 
+   <object id="ClassNode11" class="com.horstmann.violet.ClassNode"> 
+    <void property="attributes"> 
+     <void property="text"> 
+      <string>path : char*</string> 
+     </void> 
+    </void> 
+    <void property="name"> 
+     <void property="text"> 
+      <string>LocalFileSource</string> 
      </void> 
     </void> 
    </object> 
    <object class="java.awt.geom.Point2D$Double"> 
     <void method="setLocation"> 
-     <double>1119.5058052462327</double> 
-     <double>436.9433938860118</double> 
+     <double>674.5900006462128</double> 
+     <double>602.9561901969712</double> 
+    </void> 
+   </object> 
+  </void> 
+  <void method="addNode"> 
+   <object id="ClassNode12" class="com.horstmann.violet.ClassNode"> 
+    <void property="name"> 
+     <void property="text"> 
+      <string>FilterSource</string> 
+     </void> 
+    </void> 
+   </object> 
+   <object class="java.awt.geom.Point2D$Double"> 
+    <void method="setLocation"> 
+     <double>417.08326112068517</double> 
+     <double>711.364573775316</double> 
+    </void> 
+   </object> 
+  </void> 
+  <void method="addNode"> 
+   <object id="InterfaceNode3" class="com.horstmann.violet.InterfaceNode"> 
+    <void property="name"> 
+     <void property="text"> 
+      <string>«interface»
+DataSource</string> 
+     </void> 
+    </void> 
+   </object> 
+   <object class="java.awt.geom.Point2D$Double"> 
+    <void method="setLocation"> 
+     <double>1192.781692587207</double> 
+     <double>608.8954677283948</double> 
     </void> 
    </object> 
   </void> 
   <void method="addNode"> 
    <object class="com.horstmann.violet.PackageNode"> 
     <void method="addChild"> 
-     <object id="InterfaceNode2" class="com.horstmann.violet.InterfaceNode"> 
-      <void property="name"> 
-       <void property="text"> 
-        <string>«interface»
-BurnSource</string> 
-       </void> 
-      </void> 
-     </object> 
+     <object idref="InterfaceNode2"/> 
     </void> 
     <void property="name"> 
-     <string>Libburn</string> 
+     <string>Filters</string> 
     </void> 
    </object> 
    <object class="java.awt.geom.Point2D$Double"> 
     <void method="setLocation"> 
-     <double>1120.0</double> 
-     <double>270.0</double> 
+     <double>260.0</double> 
+     <double>660.0</double> 
     </void> 
    </object> 
   </void> 
   <void method="addNode"> 
-   <object idref="InterfaceNode2"/> 
+   <object id="ClassNode13" class="com.horstmann.violet.ClassNode"> 
+    <void property="name"> 
+     <void property="text"> 
+      <string>CutOutSource</string> 
+     </void> 
+    </void> 
+   </object> 
    <object class="java.awt.geom.Point2D$Double"> 
     <void method="setLocation"> 
-     <double>1131.6773781214863</double> 
-     <double>304.28653963651914</double> 
+     <double>533.842712474619</double> 
+     <double>706.7077195258237</double> 
     </void> 
    </object> 
   </void> 
   <void method="addNode"> 
-   <object class="com.horstmann.violet.NoteNode"> 
+   <object id="NoteNode5" class="com.horstmann.violet.NoteNode"> 
     <void property="text"> 
      <void property="text"> 
-      <string>Class diagram for the public tree. Note that getters and setters are not shown,
-to improve readability. Note also that not all the attributes will have public getters
-or/and setters.
-El-Torito related information is shown in another diagram.
-We don&apos;t show the several functions in Dir to manage the tree.</string> 
+      <string>Reads the contents of local files, both
+regular files, symlinks or block devices</string> 
      </void> 
     </void> 
    </object> 
    <object class="java.awt.geom.Point2D$Double"> 
     <void method="setLocation"> 
-     <double>433.2318447938257</double> 
-     <double>11.635371637423802</double> 
+     <double>836.7472580451137</double> 
+     <double>493.8376618407349</double> 
     </void> 
    </object> 
   </void> 
   <void method="addNode"> 
-   <object id="NoteNode2" class="com.horstmann.violet.NoteNode"> 
-    <void property="text"> 
+   <object id="ClassNode14" class="com.horstmann.violet.ClassNode"> 
+    <void property="attributes"> 
+     <void property="text"> 
+      <string>fd : int
+size : off_t</string> 
+     </void> 
+    </void> 
+    <void property="name"> 
      <void property="text"> 
-      <string>Each file can have several filters, that are
-applied sequentially. </string> 
+      <string>FdSource</string> 
      </void> 
     </void> 
    </object> 
    <object class="java.awt.geom.Point2D$Double"> 
     <void method="setLocation"> 
-     <double>66.59559844015237</double> 
-     <double>484.00729580610755</double> 
+     <double>846.3431457505072</double> 
+     <double>599.1219330881966</double> 
     </void> 
    </object> 
   </void> 
   <void method="connect"> 
    <object class="com.horstmann.violet.ClassRelationshipEdge"> 
     <void property="bentStyle"> 
-     <object class="com.horstmann.violet.BentStyle" field="VHV"/> 
+     <object class="com.horstmann.violet.BentStyle" field="HVH"/> 
     </void> 
     <void property="endArrowHead"> 
-     <object class="com.horstmann.violet.ArrowHead" field="TRIANGLE"/> 
+     <object class="com.horstmann.violet.ArrowHead" field="V"/> 
+    </void> 
+    <void property="endLabel"> 
+     <string>1 volume</string> 
+    </void> 
+    <void property="startArrowHead"> 
+     <object class="com.horstmann.violet.ArrowHead" field="BLACK_DIAMOND"/> 
     </void> 
    </object> 
-   <object idref="ClassNode1"/> 
-   <object idref="ClassNode2"/> 
+   <object idref="ClassNode6"/> 
+   <object idref="ClassNode0"/> 
+  </void> 
+  <void method="connect"> 
+   <object class="com.horstmann.violet.NoteEdge"/> 
+   <object idref="ClassNode4"/> 
+   <object idref="NoteNode0"/> 
+  </void> 
+  <void method="connect"> 
+   <object class="com.horstmann.violet.NoteEdge"/> 
+   <object idref="ClassNode6"/> 
+   <object idref="NoteNode1"/> 
   </void> 
   <void method="connect"> 
    <object class="com.horstmann.violet.ClassRelationshipEdge"> 
@@ -386,9 +568,27 @@ applied sequentially. </string>
     <void property="endArrowHead"> 
      <object class="com.horstmann.violet.ArrowHead" field="TRIANGLE"/> 
     </void> 
+    <void property="lineStyle"> 
+     <object class="com.horstmann.violet.LineStyle" field="DOTTED"/> 
+    </void> 
    </object> 
-   <object idref="ClassNode4"/> 
-   <object idref="ClassNode2"/> 
+   <object idref="ClassNode7"/> 
+   <object idref="InterfaceNode0"/> 
+  </void> 
+  <void method="connect"> 
+   <object class="com.horstmann.violet.ClassRelationshipEdge"> 
+    <void property="endArrowHead"> 
+     <object class="com.horstmann.violet.ArrowHead" field="V"/> 
+    </void> 
+    <void property="lineStyle"> 
+     <object class="com.horstmann.violet.LineStyle" field="DOTTED"/> 
+    </void> 
+    <void property="middleLabel"> 
+     <string>{create}</string> 
+    </void> 
+   </object> 
+   <object idref="ClassNode6"/> 
+   <object idref="ClassNode7"/> 
   </void> 
   <void method="connect"> 
    <object class="com.horstmann.violet.ClassRelationshipEdge"> 
@@ -398,27 +598,27 @@ applied sequentially. </string>
     <void property="endArrowHead"> 
      <object class="com.horstmann.violet.ArrowHead" field="TRIANGLE"/> 
     </void> 
+    <void property="lineStyle"> 
+     <object class="com.horstmann.violet.LineStyle" field="DOTTED"/> 
+    </void> 
    </object> 
-   <object idref="ClassNode3"/> 
-   <object idref="ClassNode2"/> 
+   <object idref="ClassNode9"/> 
+   <object idref="InterfaceNode1"/> 
   </void> 
   <void method="connect"> 
    <object class="com.horstmann.violet.ClassRelationshipEdge"> 
     <void property="bentStyle"> 
-     <object class="com.horstmann.violet.BentStyle" field="VH"/> 
+     <object class="com.horstmann.violet.BentStyle" field="VHV"/> 
     </void> 
     <void property="endArrowHead"> 
-     <object class="com.horstmann.violet.ArrowHead" field="V"/> 
-    </void> 
-    <void property="endLabel"> 
-     <string>* children</string> 
+     <object class="com.horstmann.violet.ArrowHead" field="TRIANGLE"/> 
     </void> 
-    <void property="startArrowHead"> 
-     <object class="com.horstmann.violet.ArrowHead" field="BLACK_DIAMOND"/> 
+    <void property="lineStyle"> 
+     <object class="com.horstmann.violet.LineStyle" field="DOTTED"/> 
     </void> 
    </object> 
-   <object idref="ClassNode3"/> 
-   <object idref="ClassNode2"/> 
+   <object idref="ClassNode11"/> 
+   <object idref="InterfaceNode1"/> 
   </void> 
   <void method="connect"> 
    <object class="com.horstmann.violet.ClassRelationshipEdge"> 
@@ -428,27 +628,59 @@ applied sequentially. </string>
     <void property="endArrowHead"> 
      <object class="com.horstmann.violet.ArrowHead" field="TRIANGLE"/> 
     </void> 
+    <void property="lineStyle"> 
+     <object class="com.horstmann.violet.LineStyle" field="DOTTED"/> 
+    </void> 
    </object> 
-   <object idref="ClassNode7"/> 
-   <object idref="ClassNode2"/> 
+   <object idref="ClassNode10"/> 
+   <object idref="InterfaceNode1"/> 
+  </void> 
+  <void method="connect"> 
+   <object class="com.horstmann.violet.ClassRelationshipEdge"> 
+    <void property="endArrowHead"> 
+     <object class="com.horstmann.violet.ArrowHead" field="V"/> 
+    </void> 
+    <void property="lineStyle"> 
+     <object class="com.horstmann.violet.LineStyle" field="DOTTED"/> 
+    </void> 
+   </object> 
+   <object idref="ClassNode10"/> 
+   <object idref="InterfaceNode3"/> 
   </void> 
   <void method="connect"> 
    <object class="com.horstmann.violet.ClassRelationshipEdge"> 
     <void property="bentStyle"> 
-     <object class="com.horstmann.violet.BentStyle" field="HVH"/> 
+     <object class="com.horstmann.violet.BentStyle" field="VH"/> 
     </void> 
     <void property="endArrowHead"> 
      <object class="com.horstmann.violet.ArrowHead" field="V"/> 
     </void> 
     <void property="endLabel"> 
-     <string>1 root</string> 
+     <string>1</string> 
     </void> 
     <void property="startArrowHead"> 
      <object class="com.horstmann.violet.ArrowHead" field="BLACK_DIAMOND"/> 
     </void> 
    </object> 
-   <object idref="ClassNode0"/> 
-   <object idref="ClassNode3"/> 
+   <object idref="ClassNode9"/> 
+   <object idref="InterfaceNode1"/> 
+  </void> 
+  <void method="connect"> 
+   <object class="com.horstmann.violet.NoteEdge"/> 
+   <object idref="ClassNode8"/> 
+   <object idref="NoteNode3"/> 
+  </void> 
+  <void method="connect"> 
+   <object class="com.horstmann.violet.ClassRelationshipEdge"> 
+    <void property="endArrowHead"> 
+     <object class="com.horstmann.violet.ArrowHead" field="V"/> 
+    </void> 
+    <void property="lineStyle"> 
+     <object class="com.horstmann.violet.LineStyle" field="DOTTED"/> 
+    </void> 
+   </object> 
+   <object idref="ClassNode11"/> 
+   <object idref="ClassNode8"/> 
   </void> 
   <void method="connect"> 
    <object class="com.horstmann.violet.ClassRelationshipEdge"> 
@@ -458,9 +690,22 @@ applied sequentially. </string>
     <void property="endArrowHead"> 
      <object class="com.horstmann.violet.ArrowHead" field="TRIANGLE"/> 
     </void> 
+    <void property="lineStyle"> 
+     <object class="com.horstmann.violet.LineStyle" field="DOTTED"/> 
+    </void> 
    </object> 
-   <object idref="ClassNode6"/> 
-   <object idref="ClassNode1"/> 
+   <object idref="ClassNode14"/> 
+   <object idref="InterfaceNode1"/> 
+  </void> 
+  <void method="connect"> 
+   <object class="com.horstmann.violet.NoteEdge"/> 
+   <object idref="ClassNode14"/> 
+   <object idref="NoteNode2"/> 
+  </void> 
+  <void method="connect"> 
+   <object class="com.horstmann.violet.NoteEdge"/> 
+   <object idref="ClassNode11"/> 
+   <object idref="NoteNode5"/> 
   </void> 
   <void method="connect"> 
    <object class="com.horstmann.violet.ClassRelationshipEdge"> 
@@ -471,8 +716,20 @@ applied sequentially. </string>
      <object class="com.horstmann.violet.ArrowHead" field="TRIANGLE"/> 
     </void> 
    </object> 
-   <object idref="ClassNode5"/> 
-   <object idref="ClassNode1"/> 
+   <object idref="ClassNode13"/> 
+   <object idref="ClassNode9"/> 
+  </void> 
+  <void method="connect"> 
+   <object class="com.horstmann.violet.ClassRelationshipEdge"> 
+    <void property="bentStyle"> 
+     <object class="com.horstmann.violet.BentStyle" field="VHV"/> 
+    </void> 
+    <void property="endArrowHead"> 
+     <object class="com.horstmann.violet.ArrowHead" field="TRIANGLE"/> 
+    </void> 
+   </object> 
+   <object idref="ClassNode12"/> 
+   <object idref="ClassNode9"/> 
   </void> 
   <void method="connect"> 
    <object class="com.horstmann.violet.ClassRelationshipEdge"> 
@@ -482,12 +739,29 @@ applied sequentially. </string>
     <void property="endArrowHead"> 
      <object class="com.horstmann.violet.ArrowHead" field="V"/> 
     </void> 
+   </object> 
+   <object idref="ClassNode12"/> 
+   <object idref="InterfaceNode2"/> 
+  </void> 
+  <void method="connect"> 
+   <object class="com.horstmann.violet.NoteEdge"/> 
+   <object idref="InterfaceNode2"/> 
+   <object idref="NoteNode4"/> 
+  </void> 
+  <void method="connect"> 
+   <object class="com.horstmann.violet.ClassRelationshipEdge"> 
+    <void property="endArrowHead"> 
+     <object class="com.horstmann.violet.ArrowHead" field="V"/> 
+    </void> 
     <void property="endLabel"> 
-     <string>1 parent</string> 
+     <string>0..1</string> 
+    </void> 
+    <void property="lineStyle"> 
+     <object class="com.horstmann.violet.LineStyle" field="DOTTED"/> 
     </void> 
    </object> 
-   <object idref="ClassNode2"/> 
-   <object idref="ClassNode3"/> 
+   <object idref="ClassNode6"/> 
+   <object idref="InterfaceNode3"/> 
   </void> 
   <void method="connect"> 
    <object class="com.horstmann.violet.ClassRelationshipEdge"> 
@@ -498,29 +772,29 @@ applied sequentially. </string>
      <object class="com.horstmann.violet.ArrowHead" field="V"/> 
     </void> 
     <void property="endLabel"> 
-     <string>1 volume</string> 
-    </void> 
-    <void property="startArrowHead"> 
-     <object class="com.horstmann.violet.ArrowHead" field="BLACK_DIAMOND"/> 
+     <string>1 src</string> 
     </void> 
    </object> 
-   <object idref="ClassNode8"/> 
-   <object idref="ClassNode0"/> 
+   <object idref="ClassNode1"/> 
+   <object idref="InterfaceNode1"/> 
   </void> 
   <void method="connect"> 
    <object class="com.horstmann.violet.ClassRelationshipEdge"> 
     <void property="bentStyle"> 
-     <object class="com.horstmann.violet.BentStyle" field="HVH"/> 
+     <object class="com.horstmann.violet.BentStyle" field="VH"/> 
     </void> 
     <void property="endArrowHead"> 
      <object class="com.horstmann.violet.ArrowHead" field="V"/> 
     </void> 
     <void property="endLabel"> 
-     <string>0..1 src</string> 
+     <string>* children</string> 
+    </void> 
+    <void property="startArrowHead"> 
+     <object class="com.horstmann.violet.ArrowHead" field="BLACK_DIAMOND"/> 
     </void> 
    </object> 
-   <object idref="ClassNode8"/> 
-   <object idref="InterfaceNode1"/> 
+   <object idref="ClassNode3"/> 
+   <object idref="ClassNode2"/> 
   </void> 
   <void method="connect"> 
    <object class="com.horstmann.violet.ClassRelationshipEdge"> 
@@ -530,22 +804,27 @@ applied sequentially. </string>
     <void property="endArrowHead"> 
      <object class="com.horstmann.violet.ArrowHead" field="V"/> 
     </void> 
-    <void property="lineStyle"> 
-     <object class="com.horstmann.violet.LineStyle" field="DOTTED"/> 
+    <void property="endLabel"> 
+     <string>1 root</string> 
+    </void> 
+    <void property="startArrowHead"> 
+     <object class="com.horstmann.violet.ArrowHead" field="BLACK_DIAMOND"/> 
     </void> 
    </object> 
-   <object idref="ClassNode5"/> 
-   <object idref="InterfaceNode1"/> 
+   <object idref="ClassNode0"/> 
+   <object idref="ClassNode3"/> 
   </void> 
   <void method="connect"> 
-   <object class="com.horstmann.violet.NoteEdge"/> 
+   <object class="com.horstmann.violet.ClassRelationshipEdge"> 
+    <void property="bentStyle"> 
+     <object class="com.horstmann.violet.BentStyle" field="VHV"/> 
+    </void> 
+    <void property="endArrowHead"> 
+     <object class="com.horstmann.violet.ArrowHead" field="TRIANGLE"/> 
+    </void> 
+   </object> 
    <object idref="ClassNode4"/> 
-   <object idref="NoteNode0"/> 
-  </void> 
-  <void method="connect"> 
-   <object class="com.horstmann.violet.NoteEdge"/> 
-   <object idref="ClassNode8"/> 
-   <object idref="NoteNode1"/> 
+   <object idref="ClassNode2"/> 
   </void> 
   <void method="connect"> 
    <object class="com.horstmann.violet.ClassRelationshipEdge"> 
@@ -555,47 +834,45 @@ applied sequentially. </string>
     <void property="endArrowHead"> 
      <object class="com.horstmann.violet.ArrowHead" field="TRIANGLE"/> 
     </void> 
-    <void property="lineStyle"> 
-     <object class="com.horstmann.violet.LineStyle" field="DOTTED"/> 
-    </void> 
    </object> 
-   <object idref="ClassNode9"/> 
-   <object idref="InterfaceNode2"/> 
+   <object idref="ClassNode1"/> 
+   <object idref="ClassNode2"/> 
   </void> 
   <void method="connect"> 
    <object class="com.horstmann.violet.ClassRelationshipEdge"> 
-    <void property="endArrowHead"> 
-     <object class="com.horstmann.violet.ArrowHead" field="V"/> 
-    </void> 
-    <void property="lineStyle"> 
-     <object class="com.horstmann.violet.LineStyle" field="DOTTED"/> 
+    <void property="bentStyle"> 
+     <object class="com.horstmann.violet.BentStyle" field="VHV"/> 
     </void> 
-    <void property="middleLabel"> 
-     <string>{create}</string> 
+    <void property="endArrowHead"> 
+     <object class="com.horstmann.violet.ArrowHead" field="TRIANGLE"/> 
     </void> 
    </object> 
-   <object idref="ClassNode8"/> 
-   <object idref="ClassNode9"/> 
+   <object idref="ClassNode5"/> 
+   <object idref="ClassNode2"/> 
   </void> 
   <void method="connect"> 
    <object class="com.horstmann.violet.ClassRelationshipEdge"> 
     <void property="bentStyle"> 
-     <object class="com.horstmann.violet.BentStyle" field="HVH"/> 
+     <object class="com.horstmann.violet.BentStyle" field="VHV"/> 
     </void> 
+    <void property="endArrowHead"> 
+     <object class="com.horstmann.violet.ArrowHead" field="TRIANGLE"/> 
+    </void> 
+   </object> 
+   <object idref="ClassNode3"/> 
+   <object idref="ClassNode2"/> 
+  </void> 
+  <void method="connect"> 
+   <object class="com.horstmann.violet.ClassRelationshipEdge"> 
     <void property="endArrowHead"> 
      <object class="com.horstmann.violet.ArrowHead" field="V"/> 
     </void> 
     <void property="endLabel"> 
-     <string>*</string> 
+     <string>1 parent</string> 
     </void> 
    </object> 
-   <object idref="ClassNode1"/> 
-   <object idref="InterfaceNode0"/> 
-  </void> 
-  <void method="connect"> 
-   <object class="com.horstmann.violet.NoteEdge"/> 
-   <object idref="InterfaceNode0"/> 
-   <object idref="NoteNode2"/> 
+   <object idref="ClassNode2"/> 
+   <object idref="ClassNode3"/> 
   </void> 
  </object> 
 </java> 
diff --git a/doc/devel/UML/iso_tree.violet.png b/doc/devel/UML/iso_tree.violet.png
index 1cbe053..225c94f 100644
Binary files a/doc/devel/UML/iso_tree.violet.png and b/doc/devel/UML/iso_tree.violet.png differ