ShapeWriter (previously known as Shorthand-Aided Rapid Keyboarding (SHARK)) was a keyboard text input method for tablet, handheld PCs, and mobile phones invented by Shumin Zhai and Per Ola Kristensson at IBM Almaden Research Center and the Department of Computer and Information Science at Linköping University.
Using ShapeWriter text entry software, a user draws words on a graphical keyboard using a pen.
After some usage the user learns the movement pattern for the commonly used words and can write them faster than is possible on a traditional virtual keyboard.
It used a handwriting recognition algorithm that relied on dynamic programming to recognize the word patterns drawn from a lexicon.
The next version described by Per Ola Kristensson and Shumin Zhai (2004) has a fundamentally different recognition engine that can recognize 50,000 - 60,000 words with low latency.