Epson Apex-80 - Manual (Page 49)

You can create any type of character. The only restriction is that the
characters you define must follow the same rules that govern the rest of
the characters printed by the Apex80. They must fit into an 11 x 9
matrix, no dot can overlap another, and either the top or the bottom
row must be empty.
Designing Process
Suppose you want to print the scientific symbol for the planet
Mercury. Although the Apex80 has a number of special symbols, that
is not one of them. First, use a grid like the one in Figure 5-1 to plan
‘where to place the dots.
Figure 5-1.
Grid
for designing draft characters
Because the last two columns are reserved for the space between
characters, they are not included in the grid. And since most
characters do not use the bottom two rows, there is a heavy line to
indicate the usual lower limit for an Apex80 character.
When you place your dots on this grid, remember that dots cannot
go on horizontal lines, but they can go on vertical lines so long as they
do not overlap any other dots. As you design your characters, draw
5 . 2 User-defined Characters