Visual languages have long been lit pursuitofeffective communication 00- tween human and machine. Today, they are suecessfully employed for e: nd user progmmming, modeliog, rapid prototypmg, and design activities by people ofmany disciplines including arehitects, artists, children, engi neers, and scientists. Furthermore. with rapid advances ofthe Internet and Web technology, human human communication through the Web or eleo- tronie mobile deviees...