"First rolling-ball mouse" https://en.wikipedia.org/wiki/Computer_mouse#Rollkugel https://en.wikipedia.org/wiki/Computer_mouse#Rollkugel https://www.e-basteln

"First rolling-ball mouse" https://en.wikipedia.org/wiki/Computer_mouse#Rollkugel https://en.wikipedia.org/wiki/Computer_mouse#Rollkugel https://www.e-basteln.de/computing/rollkugel/rollkugel/ https://www.e-basteln.de/computing/rollkugel/rollkugel/ Engelbarts mouse didn't have a ball.