[Joel]

You can either type and Return over and over again, or you could set the text to wrap in the Text Inspector and then narrow down the shape until you get the results you want.

[MichaelG]

Thanks guys. I appreciate it. Looks like I was making it too complicated.

Michael

[Chris Heath]

As another option, you create a shape, e.g., a square, then double-click it and type a letter.

Resize the letter and shape to the appropriate size, and turn off the shape's stroke and fill (if desired), then select the shape, click the Make Table icon, then drag the bottom handle down, creating the required number of characters.

Result: A vertical set of letters (one above the other) will be displayed.

Last of all, overtype each letter with the relevant replacements.