Question

define "period structure

Answer 1

It could have several meanings, depending on context. I would look first to this meaning: A building or house that is appropriate for that time period. For instance, a telephone wire is not appropriate for a western movie (I saw one in a B movie recently). A plantation house, Greek style, with columns is appropriate for the Deep South from 1850 to 1870.

Answer 2

what items supernatural or magic origin are in his study dr heidegger's experiment