Graffiti (Palm OS)
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![A chart of the Graffiti characters [(full size)]](http://en.wikipedia.org/wiki/Image:Palm_Graffiti_gestures.png "A chart of the Graffiti characters [(full size)]")
Graffiti is the handwriting recognition software used in PDAs based on the Palm OS. Graffiti was originally written by Palm, Inc. as an alternate recognition system for the Apple Newton MessagePad, when NewtonOS 1 couldn't recognize handwriting very well at all. Graffiti also runs on the Windows Mobile platform, where it is called "Block Recognizer," and on the Symbian UIQ platform as the default recognizer.
The software is based primarily on a neography of upper-case characters that can be drawn blindly with a stylus on a touch-sensitive panel. Since the user typically cannot see the character as it is being drawn, complexities have been removed from four of the most difficult letters. "A'" "F", "K" and "T" all are drawn without any need to match up a cross-stroke.
The original Graffiti system was the subject of a lawsuit from Xerox, claiming it violated Xerox's patent relating to its Unistrokes technology ([U.S. Patent 5,596,656], granted in 1997). The Unistrokes technology was invented at the Palo Alto Research Center (PARC) by David Goldberg. Palm got a demonstration of Unistrokes from PARC before they created their Graffiti system. During the original case, a court ruled that Palm violated Xerox's patent and ordered them to discontinue use of the original Graffiti system in further versions of its Palm OS software, which Palm did. It replaced the original Graffiti system with a licensed variant of the Jot system from CIC, which Palm refers to as Graffiti 2. It differs from the original Graffiti system in various ways, though it does recognize some of the original keystrokes (except the input method for punctuation and "i", "k", "q", "t").
Palm later appealed the original court ruling both on the claim it violated Xerox's patent and as to the validity of the patent in the first place. An appeals court ruled in favor of Xerox with regard to the original ruling that Palm had violated its patent but sent the case back down to the lower court to decide whether the patent was valid to begin with. In 2004, a judge ruled in favor of Palm, saying Xerox's patent was not valid on the basis that "prior art references anticipate and render obvious the claim."
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