gridsleep said: I'm tempted to add a tag for "Electronic Arts" due to the veiled reference of their symbols.
TouhouWiki said: The three symbols are related to Gibon Sengai's Picture Circle, Triangle, Square (or Three Dimensions of Somatic Attunement). This picture is so esoteric that there are several interpretations on it, but the significane(sic) of the three diagrams would be mentioned by Rinnosuke Morichika in Chapter 22 of Curiosities of Lotus Asia.