Cipher or unknown language - historical perspective

[Jorge_Stolfi]

I have numbered all characters of your picture which can be done in one stroke.

While those characters could be drawn in one stroke, most were not. As Marco pointed out, when writing with a quill on rough vellum, you can only make light strokes in the general "up" direction, because the quill risks snagging on the bumps and dents.  

All the characters you marked "1", except the i  and the n, were drawn with two strokes.  In some cases that is clear, in others it is uncertain.  Nowhere there is definite evidence that they were drawn as one stroke.

The alphabet was indeed optimized for writing, but the minimum number of strokes, for most characters, was 2.

All the best, --stolfi