Amongst the many symbols, the two key symbols that caught my attention the most were the apple and the train. The anime makes many references to Kenji Miyazawa's "Gingatetsudou no Yoru", or "Night on the Galactic Railroad" in English. I've only watched the anime version, but I highly recommend anyone who may find this anime to be of quality to look into "Night on the Galactic Railroad", either the film or the book.
The apple is a constant symbol that is continually discussed throughout the entire anime. In episode one, two young boys debate what the meaning of "the apple" is, which is the first reference to the Galactic Railroad. One boy explains that the apple is the universe itself, and that it connects this world and the other world. This dialogue comes up in the last episode at the very end, and there the two boys are actually resembling younger Kanba and Shouma. The director artfully reconnects you back to the start with that simple dialogue, which I think is a whole theme of the story with the flashbacks.
The subway-train has multiple symbols. The one that connects to the Galactic Railroad is, well, in the name itself. The other meaning behind the story of Mawaru Penguindrum is the subway sarin incident that occurred 16 years ago from when this anime was produced, in Tokyo. The majority of Mawaru Penguindrum takes place on the Marunouchi-line, which is the subway line that the sarin incident happened.
I focused on two symbols that stood out to me, but I'm sure there are many more that I'm not even aware of, from just watching it through once. Mawaru Penguindrum is definitely the type of story that makes you want to go back and re-watch scenes to get a better understanding, because of all the flashbacks that jumps randomly, and the small details. But if it were just because of the story-line, I probably won't be so drawn to watch this over again. It's the anime as a whole- the art, the music, the characters, and most importantly, the intension behind the creators, all those components combined, that makes this anime so wonderful. And I haven't even begun to mention the emotional side of the anime.
