The computer mouse was a pointing device invented in the 1960s by Douglas Engelbart as a means of avoiding the use of the finger to smear dirt and oil on glass particularly at ATMs and PoS stations.
Wow, this brought back a bunch of memories.
"I ran out of mouse pad." "That's ok grandma just pick the mouse up and put it down where you want it." Picks up mouse, puts it down in the same place "Ok now what?"