My reaction to this thread, reading the title, was to say to myself in my head (not too seriously), "Is that possible?". Then the thought (again, not particularly seriously) "Well, I suppose if it's their special interest". I've no idea if my inclination to think aspies would have bad handwriting is correct. Maybe I'm projecting from myself (I'm klutzy -- an aspie trait; figuring bad handwriting is related), or maybe I'm projecting from the aspie-ish people I know.
But, even if it is typical (not a given), that doesn't mean it's universal. And, yeah, I do think, additional, working at good handwriting can work and result in good handwriting.
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not aspie, not NT, somewhere in between
Aspie Quiz: 110 Aspie, 103 Neurotypical.
Used to be more autistic than I am now.