While wave watching is a favorite pastime of beach-goers, few notice what is happening in the shallowest water. A closer look by two applied mathematicians has led to the discovery of interacting X- and Y-shaped ocean waves that may help explain why some tsunamis are able to wreak so much havoc.<img src="http://feeds.feedburner.com/~r/sciencedaily/~4/yhthFveySt8" height="1" width="1"/>
