Max:
What struck me earlier, more than with the Latin maybe, is the high contrast between black and white, shape and space. I'd like to suggest to investigate a more equal balance, somehow. I have no straight answer or solution. It's just a feel.
Especially with lengthy vertical lines and the dots. If they would be twice as thick or twice as big, it might look different. But of all, I think Arabic option 2 come closest. I inverted the comparing picture. I like the visual appearance of the left blocky version and the right, more rhythmic version. Still, the dots become quite small details. I don't know if we can work around those...
Naji:
I see what you mean, I actually tried my best in order to create the same contrast in Arabic (as in Latin). I kind of let down the 2nd option because I found the type design was so rudimentary and esthetically weak. If I follow what you said, the black space (which will be converted to white at the end) of the Arabic letters should be thicker and covering more white space, especially for the verticals and for the dots. The whole exercise in Arabic is to try to occupy as much as space in one block, thing that is easier to apply in Latin especially with capital letters (thing that doesn't exist in Arabic). And what I noticed while designing the Ar letters is that most of letters have a latin "L" shape and a reversed "L", this makes it harder to fill the whole block in order to create as much as contrast possible, but I think finally I'll be applying the same proportions of the "L" letter in Latin following your design.
I'll try to solve this out during the evening and see what I can come up with.
I imagine that you will be able to recreate the same Latin design with the actual 15x13 grid, or shell we change it? using something with less squares will limit the Arabic design , as you can see some of the letters shapes turn around and inside out.
I'll post you up with all new. "La machine est en marche".