The invention of letters and the printing press suggested a new combinatory way of thinking. This chapter argues that both the movable type press and the cipher wheel utilized reproducible, modular, indexical, and combinatory forms of representation. In effect, the cryptographic technology Leon Battista Alberti developed was a new kind of writing, which offered unique capacities for technical representation. The history of mimesis reveals its connections first and foremost in the process of making art, but since it is a flexible theory of representation, it also works for many modes of expression. In late Modernity, scholars like Descartes would continue to modulate mimetic theory, arguing that the category of resemblance should be removed entirely from modern epistemology, and scholars such as Leibniz would develop similar notational systems specifically for "computation". Alberti's cipher wheel is more than a handy mechanism for common substitution ciphers; the key cryptographic innovation is the use of multiple alphabets in situ.