<!-- Acknowledgement: Roger Costello -->
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
           elementFormDefault="qualified">

    <xs:element name="Example">
        <xs:complexType>
            <xs:sequence>
                <xs:element name="Transportation">
                    <xs:complexType>
                        <xs:sequence>
                            <xs:element name="mode" type="modeType" />
                            <xs:choice>
                                <xs:element name="airplane" type="xs:string" />
                                <xs:element name="boat" type="xs:string" />
                                <xs:element name="car" type="xs:string" />
                            </xs:choice>
                        </xs:sequence>
                    </xs:complexType>
                </xs:element>
            </xs:sequence>
        </xs:complexType>
    </xs:element>

    <xs:simpleType name="modeType">
        <xs:restriction base="xs:string">
            <xs:enumeration value="air"/>
            <xs:enumeration value="water"/>
            <xs:enumeration value="ground"/>
        </xs:restriction>
    </xs:simpleType>

</xs:schema>