Copyright: Copyright 1998-2001 W3C (MIT, INRIA, Keio), All Rights Reserved.
See http://www.w3.org/Consortium/Legal/.
Author: Aaron M. Cohen   
         File Name: layout-hierarchical1.smil
  Media Components: 2 JPG
 Expected Behavior: Tests hierarchical layout.
                    show smile and frown for 10s, begin at the same time, smile will obscure frown.
                    show nothing for 2s.
                    show smile and then 1s later, frown for 10s, obscurring smile.
                    show nothing for 2s.
                    show smil for 10s, frown is obscurred.
<smil xmlns="http://www.w3.org/2001/SMIL20/Language">
           <root-layout width="640px" height="480px"/>
           <region id="whole" top="0px" left="0px" width="640px" 
                                        height="480px" z-index="5"/>
           <region id="right" top="0px" left="0" width="640px"
                                        height="480px" z-index="4">
               <region id="inset" top="140px" left="80" width="320px" 
                                        height="300px" z-index="6"/>
               <region id="inset2" top="140px" left="80" width="320px" 
                                        height="300px" z-index="6"/>
               <region id="inset3" top="140px" left="80" width="320px" 
                                        height="300px" z-index="7"/>
                       <img id="A" region="whole" src="../images/smile.jpg" dur="10s"/>
                       <img id="B" region="inset" src="../images/frown.jpg" dur="10s"/>
                <par dur="2s"></par>
                        <img id="D" region="inset2" src="../images/frown.jpg" begin="1s" dur="10s"/>
                        <img id="C" region="inset" src="../images/smile.jpg" begin="0s" dur="10s"/>
                <par dur="2s"></par>
                        <img id="E" region="inset2" src="../images/frown.jpg" dur="10s"/>
                        <img id="F" region="inset3" src="../images/smile.jpg" dur="10s"/>