This was posted, in several individual parts, a couple years back. I'm re-posting it now, since it seems to have vanished from the net.

This is a large expansion pack which has animated autotiles – these autotiles give you the ability to create rivers and waterfalls of sand, as well as pits of quick-sand! It was based on the RTP sand tile, so I guess it's technically frankenpixled rather than original. For RPGM XP.

Preview:

Download the ZIP file HERE