How easy is it to create a cipher which is very hard to break?

[-JKP-]

if you encoded a paragraph with the beginning and ending coordinates of a shape inside a monogram, the frequency distribution of each coordinate pair and its location within words, would match the distribution and location of the letters it encodes in whatever language it is.


In other words, a b c and 101-102, 54-32, 21-10  will be the same in how they will be distributed within a paragraph regardless of how you write them (letters, numbers, coordinates, unique symbols), and that gives it away. It's still a substitution cipher.