Answered in the article: In certain places, the script was more cramped or more likely to slant as it crossed the page. She tested this observation by picking

Answered in the article: In certain places, the script was more cramped or more likely to slant as it crossed the page. She tested this observation by picking a letter that didn’t appear often and tracking it across the manuscript’s pages. Its style, she saw, varied among groups of pages but not within those groups. This suggested that the differences—larger or smaller loops, straighter or curvier crossbars, longer or shorter feet—were the product of different scribes rather than of one scribe writing the same letter in different ways. To reduce the possibility of selection bias, Davis examined other letters and found that their styles shifted in lockstep with the first letter. After months of analysis, she concluded that even if the Voynich had a single guiding vision, it was the handiwork of five different scribes.