Z Chamber 12 Developer Commentary
This was chamber 09 (and chamber 11 in the code) in PortalZ: The 2020 Slice.
Developer commentary may include spoilers; I recommend you finish PortalZ before reading further.
This first room makes it impossible to miss the point: there are gravity fields that turn on and off. There are other ways this could have been introduced, but I liked the idea of a big room full of things that rise to the ceiling at your command. The pillar is also big enough that, while you can still see the exit door indicators, attention is still squarely on the gravity field indicator.
This room introduces uses of gravity fields that will become more important in chamber twelve—specifically, using them to perform wall-to-floor jumps and buttons that create their own fields to hold cubes to them. The chamber layout even makes the player walk past the latter a second time to get to the exit.
The floor button could have activated the box dropper directly, but it was not obvious to all players that that was the case. Having it activate a pedestal button that the player had to press made that connection more apparent.