Most common writing system
for the blind
Braille characters are made of raised dots, lined up like so:
The basic alphabet is easy to learn, ten symbols for A - J, repeated with one extra dot for K - T, 5 more with yet another added dot for U - Z (with the exception of W, there was no W in the french alphabet when Louis Braille made this up.)
Unfortunately, reading dots with your finger is slow comparared to visually reading text. To combat this, a complex system of contractions and abbreviations was developed using the remaining combinations of dots and by leaving letters out of certain long words.