Disposition temporelle : Imbrication des éléments `par` et `seq`

<seq>

    <par>
        <text src="leader_title.html" region="m_title" dur="5s" />
        <video src="cnn.mpv" region="V-main" />
        <audio src="cnn.aiff" region="music" />
    </par>

    <par>
        <text src="story_title.html" region="m_title" dur="2s" />
        <video src="anchor.mpv" region="V-main" />
        <audio src="anchor.aiff" region="music" />
    </par>