Developer website: Meilenstein Software GmbH
According to research at an English university, it doesn't matter in what order the letters in a word are, only that the first and last letters are at the right places. The rest can be a total mess and you can still read it without a problem. This is because we do not read every letter by itself, but the word as a whole.
Try this for yourself with LetterMess.
Mac OS X 10.1.5 or later