This machine is so useless, I can't imagine why you'd want to build it.  I did try to write the code so that it could be extended to buildings with different floors and Poisson distributed stochastics.  There are only really two parts to the machine: the panel, and the PC board.

Steal the indicator panel from your favorite building.  Ok... we're grownups now.  3D print an exact replica of the indicator panel from your favorite building.

Modify the schematic and PC board to fit your panel, and have your favorite fab place [e.g., my hometown favorite] make you a couple of boards [or do it old school with blue transfer, an iron, and hot ferric chloride in one of your best sauce pans].  Solder all of the parts down.  Read my log for things that bit me in the hind.

Modify the Arduino code [see my Github repo] to describe your building model [especially the number of floors and the probability matrices].

Attach the PC board to your display panel, program and insert your Arduino, and giggle yourself senseless [which, of course, I did NOT do!].