Update: Our correspondent David Schwing has been studying the career of the developer John McSorley. See his comment below, where he identifies these as two of McSorley’s buildings. The one for which old Pa Pitt could not find a name is called the Ontario.
Another update: We have found that the architect of the Ontario was the Chicago firm of Perry & Thomas.(1)
The intersection of Maryland and Ellsworth Avenues in Shadyside is flanked by apartment buildings with distinctive rounded corners. Above, the Panama. Below, a building that must have looked very modern when it was put up (in the original version of this article, we said “probably around 1920,” but it turns out to have been 1911, which makes it even more strikingly modern); it seems to have no name but its addresses. (Addendum: It was originally called the Ontario.)