In terms of my previous blog entry I just wanted to add that if the gentile would bow down to the brick without the Israeli having set it up to be served, the brick would not be forbidden to derive benefit from (since the gentile does not own the brick). So it is just the setting it up by the Israeli which makes it prepared to receive idolatrous worship which makes it forbidden after the worship was done. So when the Rambam says "the setting it up is an act" he means it causes a "halut" [state of being]. There is no question about what the law is, but rather what does the  Rambam mean by words "setting up the brick is an act''.

[The brick is just an example. Worship of any physical object would be the same thing. And worship means bowing, burning incense, bringing close to an altar, slaughter of an animal before it, or doing a kind of service that is specified for that idol. And example would be throwing a stone at Markulit which is its service. And the physical object does not have to be a statue. It would be anything except for the One First Cause. This I hope might bring clarity to why I say that the religious world is really doing idolatry, and why the Gra signed the letter of excommunication.] [The reason for the Gra might not have been clear at the time, but nowadays it is crystal clear]

I want to mention that Rav Shach answers the obvious question n the Rambam by putting setting up the object is an act by the egg.