When you look at enough church arrangements over the years, you begin to pick up on patterns and can start to discern particular styles. One which has been particularly evident to me for some while is a particular form of altar found in the north of Italy, particularly Milan -- the territory of the Ambrosian rite -- which presumably developed in the counter-reformation period.
The form is fairly straight-forward; an altar with two or more gradines (frequently adorned with reliquary busts) and a circular, domed canopy which covers either the tabernacle or altar cross. An example:
Of course the most famous example of this arrangement could historically be found within the primatial cathedral itself, the Duomo of Milan:
It seems to be quite possible that the other, similar arrangements that can be found elsewhere throughout the archdiocese of Milan may well have come in imitation of the cathedral church arrangement, but this is purely speculation on my part.
Here are a few other examples of similar altar arrangements found throughout the See of Milan:
Regrettably, I can offer little in the way of specific historical comment around this, but it seemed an interesting stylistic marker worth pointing out all the same. Most of the time, if you see an altar coming in this particular form, it is quite likely Milanese.