Now that is one beautiful machine...

I once had an idea for a fully analog SLA printer that would use a set of line etched slides and expose the bed to a flash of sunlight through the slide per each layer, switching slides based on some kind of notch or hole mechanism in the edge of it... It ended up being much more complex, even on paper, than I have time for.

I definitely think this approach is more simple though (and doesn't require a person constantly adjusting a mirror to catch the sun, that's a plus)