My brother built a ram jet engine in high school. It was the same design as the V1 rockets had in WW2.
That was 22 years ago. There was no CNC back then, at least not 5-axis.
He also built a 6 cylinder steam engine that only had 5 moving parts. He built that when he was 15 years old!
Any guesses how you could have 6 cylinders and only 5 moving parts?