system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How was the straight line invented?

It is said there are no straight lines in nature.  There are things that come very close to straight (a weight at the end of a string), and maybe even things that are arguably straight (crystal structures at the ionic level).  To create anything straight (or flat if considering an additional dimension), we must use a straight stencil or tool.  How did we get to the point where we can create perfectly straight edges and flat surfaces (at least down to the molecular level)?
gpt
You're mistaken. The easiest way to make a straight line is to pull a string tight. It's extremely easy.

The second easiest way is to look from one point at another point, and mark the items that are directly in the path.