<grammar datatypeLibrary="http://www.w3.org/2001/XMLSchema-datatypes"
  ns="http://relaxng.org/ns/structure/1.0"
  xmlns="http://relaxng.org/ns/structure/1.0">

  <start>
    <ref name="listOfLists"/>
  </start>
  
  <define name="listOfLists">
    <element name="listOfLists">
    <group>
      <zeroOrMore>
         <ref name="listOfLists"/>
      </zeroOrMore>
    </group>
    <optional>
      <attribute name="fail"/>
    </optional>
    </element>
  </define>
</grammar>