Reading about code is one thing. Watching it run is another. Below are 15 real programs, stepped one beat at a time across six panels: the variables as they change, the arithmetic as it's worked out, the source line lighting up, memory — the stack of frames on the left, the objects on the heap on the right — and every step narrated twice: once in plain words, once under the hood.
How to use it: press Next (or the → key) and predict what the next beat will show before you look. Part A steps through the nine core mechanisms of the machine model — labels and refcounts, lists growing, dicts hashing, frames pushing and popping. Part B steps through six real programs where those mechanisms do real work — including one with a genuine bug you get to watch happen.
Predict → step → check. That loop is the whole method.