It was Jim’s first day on the job at Amalgamated Eye Charts. He learned that AEC uses the traditional Snellen chart, which is printed with eleven lines of block letters. The first line consists of one very large letter, always E, H, or N. Subsequent rows have increasing numbers of letters that decrease in size. Mr. Fleen explained that symbols on an acuity chart are formally known as “optotypes.” On AEC’s Snellen chart, the optotypes have the appearance of block letters, and are intended to be seen and read as letters. They are not, however, letters from any ordinary typographer’s font. They have a particular, simple geometry in which the thickness of the lines equals the thickness of the white spaces between lines and the thickness of the gap in the letter “C”, and the height and width of the optotype is five times the thickness of the line. Only the ten Sloan letters C, D, E, F, L, N, O, P, T, Z are used.
Jim would be starting in Paper Prep, but if things went well, a man of his caliber could move to Fonts or even Line Writing by Christmas. Jim wanted to be a writer. He wasn’t listening now. He was thinking about how FLEEN could be written using only Sloan letters, while his name contained none.