The most common
type of synesthesia is grapheme to color. This is where the person with
synesthesia sees letters and numbers as having colors. There's
also grapheme personification, where the synesthete perceives the letters and
numbers as having personalities and/or relationships with other letters and
numbers. Another form of synesthesia is object personification, when the
synesthete perceives objects as having personalities or relationships with
other objects.
Here's my numbers and alphabet.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
1 2 3 4 5 6 7 8 9 0