1<?xml version="1.0"?>
2<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
3  <xs:complexType name="length2">
4    <xs:complexContent>
5      <xs:restriction base="xs:anyType">
6        <xs:sequence>
7          <xs:element name="size" type="xs:nonNegativeInteger"/>
8          <xs:element name="unit" type="xs:NMTOKEN"/>
9        </xs:sequence>
10      </xs:restriction>
11    </xs:complexContent>
12  </xs:complexType>
13  <xs:element name="depth" type="length2"/>
14</xs:schema>
15