Also, I acted upon the advice and decided to look through Victorian era, in order to find inspiration for the machine. Here are the silhouettes I managed to make so far:
Three further developed projects:
"(...) we emerged from our chamber into the cavern from which the light had come (...). But at last the great place that formed a background to our movements asserted itself."
First two concepts of the cavern.
In the first picture I started by drawing the machine. To be honest, I found it so amusing, that I decided to take it a step further and that's when all these additional "mysterious apparatus" projects came from.
From now on, I would like to focus on the surroundings and environment more, than on the machine itself, although I'm going to come back to it when doing the final concept.