I want to see a computer interface designed for a four-armed person
probably something along the lines of a three-handed keyboard plus a mouse?
but what would that three-handed keyboard layout be like? or would there even be a four-handed keyboard?
It's not just right up my alley, it's why Ringoid Labs was founded (although they've since branched out to building devices and furniture for all kinds of variant body shapes). Their original four-handed computer setup was a standard two-handed keyboard and then either a mouse and an extra symbol keypad or two keypads. These could be moved independently of the main keyboard to wherever is comfortable, and came in different varieties depending on the user's needs. If you're writing scientific papers, you'd need different buttons than if you're building 3D models or composing music.
@Felthry all I can think is four arms mean you can use your computer keyboard and drink tea at the same time.
Or type really fast on the right kind of keyboard.
@dodec I think this kind of pondering would be up your alley