To Kate in April - pop art font

Here is a new type of puzzle - or *new to me* I should say.

It appeared in Morning Brew - something that pops up in my email every morning to offer tidbits of news which often times get my blood boiling -- and then at the bottom they have a variety of puzzles and quizzes. 

The *puzzle* blurb said: what is *unique* about this sentence. I didn't spend any time trying to figure it out - and will post the answer in a paragraph below - but, I need something to fill the space before I post the answer - so I will talk about that envelope.

This is the *puzzle* - What is unique about this sentence:

I do not know where family doctors acquired illegibly perplexing handwriting.

I'm  auditioning styles to go with the Roy Lichtenstein stamps that will come out one of these days. I just read the Wiki article about Roy. Lots of details - mostly confirms that his work was controversial when he did it and it's still controversial. Somehow - being controversial is sometimes *the subject matter* of art. And even that is controversial. OK - here is the answer to the puzzle: It’s a “snowball sentence”: The first word is one letter, the second word is two letters, etc. Can you write your own snowball sentence? This is as far as I got.

I am not blue about orange jumpers