Now that we have some basic control over individual media let's see how we play them together.
The <seq> tag is used to define a sequence of media.
.....
<seq>
<img src="img1.gif"
region="reg1" dur="6s" />
<img src="img2.gif"
region="reg2" dur="4s" begin="1s" />
</seq>
.....
So the setting 1s makes the img2.gif icon appear 1 second after img1.gif.