<?xml version=“1.0”?> <xs:schema xmlns:xs=“www.w3.org/2001/XMLSchema”>

<xs:complexType name="length2">
  <xs:complexContent>
    <xs:restriction base="xs:anyType">
      <xs:sequence>
        <xs:element name="size" type="xs:nonNegativeInteger"/>
        <xs:element name="unit" type="xs:NMTOKEN"/>
      </xs:sequence>
    </xs:restriction>
  </xs:complexContent>
</xs:complexType>
<xs:element name="depth" type="length2"/>

</xs:schema>