My dad had to sign up for service in the military in Britain in the late 1940s when he turned 18. He never told me exactly how he got out of it (I suspect he pretended to be gay), but he did tell me about the "intelligence test" he had to take which sounded very similar to the cognitive diagnostic test Trump brags about. He said it was stuff like-

Which of these doesn't belong: Square, circle, triangle, elephant.

He finished it in about five minutes, asked if he could leave, and was told he had to wait until everyone finished or an hour had gone by. Apparently, by the end of the hour, there were people around him really struggling to finish.