Happy-go-lucky Harry decides to open his computer case to se…

Happy-go-lucky Harry decides to open his computer case to see what he can see. After a few moments of pondering, he notices three cables connect to the motherboard. He pulls at one and disconnects it from the motherboard. Delighted at his success at removing something, he pulls out all but one cable. He is interrupted by a phone call and when he returns, he realizes that he has forgotten which direction the cables face to be correctly reinserted into the board. What is the simplest thing you can do to solve Harry’s problem?