A high school paper.
I wrote a paper in high school saying that people should have their skin color noted on their fore-arm and all mankind would be divided into 20 shades. No one would be allowed to procreate within 5 shades of their own color.
After a few generations there would be 15 shades, and within 3 shades, and so on.
Utterly impractical, certainly would have brought globalization along a bit earlier.