I know this is a joke but here comes my two cents:

1. Create a hidden folder called .free_energy_designs
2. Put some random images of pyramids in there
3. Use VeraCrypt to encrypt with secret second encryption layer where you store your porn

Just rename it to homework, like a civilized person.

Why hide it? But unless you normally have hidden files shown you could just put a period at the start of the folder name and then it'll be hidden (works on windows too). Generally you'd put all that stuff in the home folder for your user, so "/home//.notporn/"

ReactOS and windows use almost the same file system

There efficency gains to small file names, less data to type or handoff to the kernal, less text on the screen from ls