Seattle-area startup Puzzazz began as a creator of online, mobile, and e-book puzzles. But they’ve established a new core technology that might end up being a bigger draw than their Sudoku apps. They call it TouchWrite, and it lets you draw letters and numbers directly on the screen instead of tapping them on the on-screen keyboard.A modest achievement in some ways — basic handwriting recognition goes back decades — but the fact is that the ability to draw a B or 7 right on the screen is handy, and more natural to puzzle-doers than the alternative. But more importantly, it’s a fundamental method of interaction that none of the touchscreen e-readers have implemented, and Puzzazz is in a position to make their solution the official one.