You're not limited to "a machine that executes code" (even as simple as a Turing machine) and "reading your program in your head." Most 8-bit processors were e

You're not limited to "a machine that executes code" (even as simple as a Turing machine) and "reading your program in your head." Most 8-bit processors were easily comprehensible by people, and could be represented in a simple state machine. That state machine can be emulated by anyone with pencil and paper, albeit at a billionth the actual execution speed. But walking through assembler that you hand-compile to machine code, and then step through rigorously with a constant eye towards what the processor is doing and how it does it is probably far more valuable than any certificates.