Rotwangs Machine-Man is the most magical technology seen in the film. This is understandable since there the only common precedent available to the audience were stories of golems and imps, soulless and wicked servants out to wreck havoc at their masters bidding. Despite this imp paradigm, many of the interfaces around the Machine-Man are worthy of note.
Rotwang reveals the Machine-Man.
When Rotwang first reveals the Machine-Man to Joh, he does so with a dramatic yank of a curtain to the side. There sits the automaton, in a throne before a catwalk. In response to the curtains opening, the catwalk gradually illuminates. Did the Man-Machine turn the lights on? Was it a curtain switch? The movie gives no clues, but the lesson is clear. Light signals power, and the Machine-Man is imbued with a lot of it.
The Machine-Woman awaits Rotwang’s instructions.
The Machine-Man as Joh meets it is entirely machine in appearance. (Beautifully designed by Walter Schulze-Mittendorff. This piece of sci-fi is so iconic and seminal that it warrants its own Wikipedia page.) At Joh’s instruction, Rotwang gives the Machine-Man the outward likeness of Maria. How he is actually able to accomplishing this is vague, but note that as he twists up the power, more and more bars illuminate at the foot of the table. An early establishment that, as power increases, so does light.
Rotwang powers the transformation table.
This “light = power” theme is reinforced a number of times throughout this sequence.
Some machine glows as Rotwang turns it on.
With a switch the transformation begins.
Rotwang increases the power to the transformation table.
What does the tall tank, the arcing sphere, or the large wafer switch do? We don’t know. But with the flick of a switch, something glows, and even without any sound to tell us, we know that he’s summoning a great deal of power for what hes about to do next.
Machine-Maria devises her saboteur’s scheme.
Machine-Maria looks nearly identical to the real Maria. But in seeking to make the differences clear to the audience, actress Brigitte Helm needed to supply some kind of uncanny valley a century before the term was invented. Her response, which underscores the evil twin nature of Machine-Maria, was to adopt sharp, precise movements, an under-the-brow stare, and asymmetry. These simple cues let us know in a few seconds that she is not human and not to be trusted.
On the pyre, Machine-Maria reverts to her original form.
Machine-Marias death also underscores its deeply magical roots. When burning on the pillar, Machine-Maria transforms back to her original, machine-like form for little given reason other than her spell has been somehow broken.