system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: why does running scissors across ribbon make it curly?
gpt
it's actually really interesting- i used to think that it shaved off the bottom of the ribbon, but that's not it.  because the blade is sharp the cutting part is really thin and with the right pressure, it actually stretches the far side of the ribbon more than the close side, resulting in a curl. and it stays that way.