visual query tools: SHOE/PARKA applet

I just stumbled across a rather neat Java-based query demo on the
SHOE/PARKA site. 

http://www.cs.umd.edu/projects/plus/SHOE/binpiq.html (older binary-relations)
http://www.cs.umd.edu/projects/plus/SHOE/piq.html (new n-ary relation)

The two versions of the applet correspond to SHOE's evolution from an
RDF-like binary relations model to a full n-ary relations approach. The
Java applet demo allows the graphical creation of queries. Basically it's
a simple visual graph editor with the ability to flag each node in the
graph as a variable. The query structure can then be sent to a server 
which responds with a result-set that can also be viewed in terms of the
query graph. 

For the Java-averse, there are screenshots,
http://www.cs.umd.edu/projects/plus/SHOE/images/plusquery.gif
http://www.cs.umd.edu/projects/plus/SHOE/images/pubquery.gif
(rounded nodes represent variables in these displays)

Dan