4. The computer-readable medium excluding signals, the computer-readable medium of claim 3 having computer-executable instructions to perform: (d)(i) approximating a stroke of the writing line by a polyline.
4. The computer-readable medium excluding signals, the computer-readable medium of claim 3 having computer-executable instructions to perform: (d)(i) approximating a stroke of the writing line by a polyline. 10. The computer-readable medium excluding signals, the computer-readable medium of claim 4 having computer-executable instructions to perform: (d)(i)(l) approximating the stroke by linear regression.