“She compiled three sets of books, with about 12 books in each set and no more than a dozen pages in each book. … Readers encountered only four letters — M, A, T and S — and three-letter words. The texts became gradually more complicated, as letters were added until the first set introduced everything but Q, culminating in a sequence that featured a vet, a van, a big cat and a bad leg: ‘The cat ran zig zag. The vet ran zip zap. ZAM!'”