I had a Schnauzer who did that to the keyboard on my typewriter when I rushed out (leaving him locked in the kitchen) to file a story by deadline for the weekly newspaper for which I was writing. Jumped right up on the kitchen table to leave his present.
Other days, he peed on the typewriter case I used to block the accordian baby gate where it attached to the door frame to keep him in. His message was clear!
Yup, THAT’s a schnauzer.