In small-ring chemistry, quite a lot. Cyclobutanecarboxylic acid contains a four-carbon cyclobutane ring attached to a carboxylic acid. Cyclobutane is strained.
If its four carbons formed a perfectly flat square, the bond angles would be around 90 degrees—far from the ~109.5 degrees carbon normally prefers. So the molecule does something clever. It folds.
Global Chemical Database