system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Software patents and why they are "evil"

I'm not quite sure what a software patent is, and Wikipedia doesn't have the greatest information.
Is it like the creation of a file type that others cannot use (.rar where only winRAR can make but others can unarchive)?
Or is it like a process (the way VLC opens a video file)?
gpt
A computer program is a series of instructions, like a recipe.

Suppose you're making dinner, and decide to mix certain spices together in a bowl then toast them in a pan.

It turns out well, so you publish it as part of a recipe. 

Then someone comes along and sues you, saying they invented the idea of mixing those spices together and toasting them. You protest that you didn't copy them, it was your own idea. That doesn't matter. The other guy thought of it first, and now he owns that technique for the next nineteen years. He can charge you whatever royalties he likes, or prevent you from using that technique at all.

Software patents are like that. Patents are awarded for the sort of ideas that programmers come up with all the time, as part of their everyday work. 

Getting a software patent is a lot more expensive than coming up with the "invention" in the first place, so only large corporations can afford to do it much.