Reading #8 $N recognizer

Summary
As the title suggest, this paper is an extension to $1 recognizer with an attempt to make it a multiple stroke recognizer. $N share similar goals with $1 but it's more versatile by
1.recognizing gestures comprising multiple strokes,
2. Automatically generalizing from one multistroke template to all possible multistrokes with alternative stroke orderings and directions
3. recognizing 1D gestures such as lines
4. providing bounded rotation invariance.

$N precomputes all possible permutations of stroke orders and directions in a multistroke gesture. At runtime, when a multistroke gesture is drawn, its single stroke components are connected in the order they have drawn to make a unistroke. Then the unistroke is compared against unistroke templates using euclidian distance as in $1. The best matching template is picked.