system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does dragging a scissor along a length of ribbon cause it to curl?

Wrapping gifts yesterday and currently watching *Elf*...
gpt
This is actually a well studied phenomena and the reason is pretty cool.

Basically you are stretching one side of the material more than the other side and that deformation persists after you run the blade down the ribbon.

Since one side contracts more than the other side it tends to curl naturally.