The context: a warning to a user of a website that tells the user that patterns in an image should be avoided.
One of the key characteristics of a pattern is that it is repetitive. There is no such thing as a “non-repetitive pattern”. This makes it a pleonasm. Am I right about this?
At the same time, I feel “repetitive pattern” sends a clearer message to the user than just “pattern”, because it is a pleonasm. I was taught that I should avoid pleonasms. Is this a justified case to use a pleonasm?