Why not positional variation?

[nablator]

A good question then, why some symbols can have alternate loopy forms, like m replacing r, but some others not, like there is never a loop+downstroke form of n, as far as I know. I've seen at least once in the MS a tiny loop at the top of n, but I don't think I've seen a full downstroke.

                                                       

Maybe they are badly written m or i+loop+downstroke, and the last image is a+loop+downstroke.