...I still remember from my schooldays a sentence composed of a word used ten times in succession ... I just re-counted and it's eleven not ten in succession.

Funny you should mention this, paulb. This week my daughter showed me her school newsletter with the following item in the Fun/Jokes section for the kids.

A signwriter had just finished painting the sign FISH AND CHIPS on a shop when the owner came out and complained "There's too much space between FISH and AND and AND and CHIPS."

I then introduced what I presume is the same example as yours, which I too recall from my school days.

Am I on the right track if I say it's a 3-letter word, some in quotes, and technically it's two sentences, or at least two distinct thoughts connected by a semi-colon? No proper nouns, and no iffy word usage.