The Moon alphabet: eight shapes, turned around

Moon kept the letters a newly blind reader already knows, and replaced the others with lines, curves and angles that stay apart under a finger. Turn one of them around and it becomes another letter. That is the point: fewer shapes to learn.

In this font, every shape is drawn by a rule, not by hand. Each one sits in a square cell of 1000 units, inside a body of 700. A shape only changes when its rule changes.

Learn one, and you have four letters

The RNIB teaching manual groups the alphabet into eight base shapes: five that give four letters each when turned, and three pairs. These are its own names for them.

A sign that says “a number follows”

A number takes two cells: Moon puts a sign in front of it, exactly as braille does, and then the letters A to J stand for 1 to 0. That sign was adopted in 1937, and it is the the sign turned upside down — a bar with the dot below instead of above.

Set to be read with a finger, not an eye

RNIB gives the size of a Moon character as about 8 × 8 mm, against 4 × 6 mm for a braille cell. These are screen sizes, shown so you can see the shapes; the printable sheets start at the 8 mm the guidance names.

The line is what the finger follows

The shapes are the same in all three weights. Only the thickness of the line changes, from 70 units to 130 in a cell of 1000. There is also Moon Uniform Dotty, which turns the same shapes into a 5 × 5 pattern of dots, for braille machines and pin displays.

Moon was carried into other scripts

In the nineteenth century, Moon was adapted for many languages. Greek, Cyrillic, Armenian and Arabic are in this font. The English short forms are not: they stay in English, which is where they were written down. Any sign without a source is marked as a guess on the research page.