Split the phrase and it opens. A period is one stretch of years with a look of its own; a piece is one made thing — a chair, a film, a song. Put them together and you have a made thing that carries the smell of a particular stretch of years. The only question left is how the smell got there. Sometimes the thing really came out of those years and kept them. Sometimes a maker went back and built them again on purpose. Either way, you look at it and you can say when.
From the picture
刻意把故事放回那個年代
一樣是「帶著某個年代味道的東西」，但味道不是時間留下的，是做出來的：創作者選定一個年代，再把它重新蓋起來。
noun · C1
A film, play, or book whose story is set in one particular time in the past, so that the clothes, the rooms, the music, and the way people speak all belong to that time.
時代劇；古裝片
noun · C1
An old piece of furniture or a work of art that was made in an earlier time and clearly shows the style of that time.
古董家具；時代精品
noun · C1
A film, song, book, or other work that now feels strongly of the time when it was made, even though it was never trying to show the past.
時代產物；當年味道的作品