(Partially) diagonal horizontal
The Nastaliq form of Arabic script, which is the standard form of writing Urdu, is I
think unique in the world by being written in occasionally overlapping diagonals.
The letters are connected to each other in a string that moves gradually downward,
and when a new word is started, the beginning of the word often appears above the
ending of the previous word in order to fill up space and make it more aesthetically
This is when lines of text are alternately written left-to-right and then right-to-left.
This may be accompanied by a 180° rotation of the glyphs, a result of the writing
surface having been rotated in the scribe's hands. For obvious reasons, no modern
scripts are written this way, but if you are creating an ancient script, it could be an
Some scripts are written in more than
one direction at the same time. For
example, Many (but by no means all)
Mayan inscriptions were written left to
right, but only in pairs; after two
glyphs, a new line is started below the
previous one, leading to columns two
Sumerian Cuneiform was similarly
Phrases or sentences were written
horizontally left-to-right within cells,
but the cells were arranged vertically.