That's how Q.E.D. sounds (latin phrase "quod erat demonstrandum", meaning "thus it has been...
It sounds like the system does not obey.
When someone reaches out to you for something important.
Apparently, you shall not pass!
When you have an annoying friend that tries to prove herself right.
An important announcement is about to be transmitted.
Oh what fun it is to ride in a one horse open sleigh!
Makes you think of a chirping bird, except it's a completely artificial sound.