When I'm trying to get to sleep at night, I tend to play around with words in my head. Sometimes, I'll try to make up cryptic crossword clues. A few nights ago, the word "break" came into my mind and I came up with the satisfactory clue "holiday snap". I was happy with that and drifted off to sleep. The other night, the word "by" popped into my head. Let's take the sentence "A famous song by The Beatles". Give me a synonym or substitute for "by". I certainly couldn't think of one. Even allowing myself TWO words---"performed by"...."done by"---still includes the word I want to replace.
Yes, I know I have problems.