A L^AT_EX input file can only contain the 26 upper- and lowercase letters of the Roman alphabet (A,..., Z, a,..., z), the ten Arabic numerals (0,..., 9), the following punctuation characters:

. : ; , ? ! ` ' ( ) [ ] - / * @ 

the following special characters, used only in L^AT_EX commands:

# $ % & ~ _ ^ \ { } 

and the following characters used mainly in mathematical formulas:

+ = | < > 

You should notice that there is a left quote and right quote. The left quote is produced by pushing the grave accent (`) key (located in the upper-left corner of the keyboard, to the left of the number 1). The right quote is produced by pushing the regular single quote key (on the home row to the right of the semicolon). To produce double quotes (") simply use two single quotes.

You should also note there is a forward slash (/) used in punctuation (which shares the same key as the question mark (?)), and a back slash used in L^AT_EX commands (located above the enter or return key and below the backspace or delete key).

The tilde (~), one of the special L^AT_EX commands, shares the same key as the grave accent (`), so use the shift key to produce it.

On most keyboards the curly braces ({}) are located to the right of the letter p. The pipe (|) character shares the same key as the back slash. And the less than (<) and greater than (>) symbols share the same keys as the comma (,) and period (.) respectively.

Spaces are produced with the space bar. In the input file one space is the same as 100 spaces. One or more completely blank lines will start a new paragraph.

The output file can contain almost any graphic. Including graphs, figures, pictures, mathematical symbols, text, greek letters, and many other things. Below is a sample of a L^AT_EX output file.