An interactive fiction.
Paradiddle Rox is composed of wordsquares. The first, No. 415, was written by Clive as an entry in a competition to write a science fiction story in exactly twenty five words. Four others followed, Nos. 83, 252, 668 and 929, all with exactly 25 words. Each wordsquare is assigned a number generated randomly between 1 and 961 (31*31) at random.org.
Since then the process has developed somewhat. Instead of being restricted to 25 words, 5*5 of course, wordsquares can contain n*n words: where n is any natural (whole) number between 0 and 961, the largest square less than or equal to 999. This acts as a powerful constraint on the writing of wordsquares. You will notice that wordsquares currently contain anything from 0 to 81 words.