//Warning :  do not use free-style looking fonts, for example on a basis, that it would contain 16 easy visually distinguishable symbols.
Warning :   when doing the font on a basis, that it would contain 16 easy visually distinguishable symbols, if using free-style looking fonts, watch, that they wouldn't have a symbols which already are in use.
(also mentioned in "conceptions.txt")
Because those signs may contain a people degenerative/destructive information included in them.
An example :  Old-Russian runic alphabet, "Славянские руны".

The number positioning on a bitmaps.
01.png

4 diagonal lines coming out from the character center, represent 4 binary digits.
Line presence means 1.
02.png
03.png
To avoid visual interference with neighbour symbols, the center is done bold.
(00.png template)
The order of lines representing bits :  left-top 3, right-top 2, left-bottom 1, right-bottom 0.
Lines angle does not need to be of 45 degrees.
04.png
Lines can have a short lines at their endings, to make the character be more readable.
05.png
06.png

Since 0 have no lines, it has to be done more visible, than just the center of a character with lines (which have some bits of 1).
0 can be circle or disk of any size; 50%-100% of char size is prefered.

Character root does not need to be at the center; it can be put excentric.
07.png
08.png
Bits in this case are placed in order 3 2 1 0 from left to right, or/and from top to bottom.

The second idea is that some lines (lets say bits 0 and 2) should be shorter, and not just a straight line, but like two lines or something ...
09.png
0a.png
0b.png

3 bit (bits 0, 1, 2) lines version.
4-th bit is included in the knot centering.
0c.png
0d.png
0e.png
0f.png - bad; bad difference between '4' and 'c', and between '1' and '9'.
If move the second center from the right-bottom to right-top, then still do conflict '2' against 'a', which both consist of one diagonal line.
The difference between '2' and 'a' is the hardly notable knot.
10.png
So symbols '2' and 'a' need to be corrected.
11.png

Notable is, that making a declined lines (like cursive), at once is diminishing the font readability.
0e.png for example.
So here is some cost for the readability.
Notable is nfnt3 readability loss on some two char compositions, which have the same direction, parallel lines, like 1c/c1, 49/94.
Especially unreadable, if there are only these bytes, and nothing more, by what would be possible to orient.
In that case, even 11, 44, 99, cc are unrecognizable.
Nfnt3 direction/orientation is only possible to define by '8' symbols.
Nfnt4 doesn't have most of these lacks; a dump of its 00, 11 and 88 would have unrecognizable direction, but that is very unsignific.