Believe it or not, you actually can, so long as it is part of the design of a typeface you've completely created from scratch. You are allowed to copyright the alphanumeric letters and numbers, symbols, etc, and control the use, licensing, of all versions of those letters in that typeface. . . and sue people who use it without permission!
Check what Adobe charges for the use of their typeface libraries, the complete set is something like $650, and more, if you actually print a large print run of a book.
That is pretty wild.