[0des]

Xerox guys were always a class of their own.

[deepstack]

They are the ones that made the mouse.

[LargoLasskhyfv]

They made one mouse, not the mouse.

Telefunken Rollkugelsteuerung was a little bit earlier, as an optional accessory to one of their vector graphics terminals.

https://en.wikipedia.org/wiki/Computer_mouse