You know what I just realised/remembered? Maru/a circle stands for being correct. At the start of each teaser we get a full circle splitting into four, can we derive something out of this?
Also this image contains both a maru ( O ) and a batsu ( X ), so something true and something false. Something right and something wrong.
The X is present only in this image, not during the beginning of each trailer or for the third teaser symbol. This image also has a very heavy feel, the other person is twisted and broken (or they both are). Are they being punished for doing something forbidden or are they a warning?