system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does rolling up clothes (especially t shirts) seem to save so much more space than folding them normally?
gpt
Every folded crease is like a spring because one side of the fold is compressed while the other side is stretched. For example, try folding a piece of cardboard so that both halves lie flat against each other. If you let go, it tends to spring back upwards.

Folded clothes have the same effect. Each fold acts like a spring that props up the item so that it takes up more space when it is sitting still.

When you roll clothes, you are not adding any sharp folds and the act of rolling compresses any of the existing folds. This is why it has less volume!