Strange, the S and Z look better as the opposite of the shapes I expected them to be. 15 letters are basic shapes, 3 letters are 1x2 constructs, 6 letters are 2x2 constructs, and 2 letters are 3x3 constructs.

SbB Codebreaker is my entry for the Reverse Competition. Four parallel glyph sets: Symbols, Positive, Reverse and Alphanumeric. And all with a single brick. I'm really happy with the texture of the type.