I don't understand the hydraulic press part.
First, I'd expect the press to somehow mess with the patterns, and second, I would have thought he'd just let the cement take.
Anyone knows what the point of this part?
Here is a pdf with a lot more detail:
http://www3.ipc.org.es/dms/pdfs/Baldosas_hidraulicas/Hydraul...
See also https://www.notechmagazine.com/2014/09/hydraulic-mosaic.html