In LAB RAT, each letter is a simple maze. Each letter connects to the next to make any word (or numeric expression) into a more complicated, though still left-to-right, labyrinth. (The starting point was the square-shouldered forms of the old Apple system font Chicago.) It must be seen large to be fully appreciated.
The demo version contains enough to give you the idea of how nicely it works. The full version contains the complete alphabet, numbers, and punctuation.