This is Yet Another chinese learning tool. It reads touchpad input via usb, and is able to recognize characters based on a library of stroke data (algorithm from HanziDict by Jordan Kiang, with the addition of distinguishing individual characters based on a continuous flow of strokes). It does background lookups of character etymology, stroke order, related words, application measure words, pronounciation information (all from the excellent www.yellowbridge.com) as well as the standard CEDICT data. It also has a study mode which tests your memory of characters based on their HSK ranking (using Mnemosyne's spaced-repetition algorithm), with the unique advantage that it's able to test your memory of a character by asking you to write it with your hand, which I've found to be a great help. It also presents you with a sample sentence with a blank, and you write a word which can be used there.