system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is it hard to photograph striped fabrics?

When you take a photo of a striped fabric that isn't an extreme close-up the image tends to produce a blurred wavy effect instead of showing the stripes as they are - why is that?
gpt
It's called "moiré" (pronounced mwarray) and it's to do with the way your digital camera sensor takes in and processes an image signal. 

Take a piece of paper with black parallel lines close together on it and make a copy on transparent film. Placing the transparent one on top, move their orientation away from being squared up and you will see the same effect. The bottom piece of paper is the pattern in your fabric. The top transparent piece is your cameras sensor. Both are geometric, and when one is oriented even slightly off square you will see your brain (or your cameras "brain") perceive patterns from the interaction of the shapes.

This was used to great effect in the "op art" movement. Good place to start exploring visual tricks.