Now that the black monolith is solved (I'm personally convinced the release date is the intended solution), I figured we could apply similar logic to discovering the heart room's secret. Unlike the monolith code, the heart disintegration codes are RT/LT only. To me, this means it could be something similar to the observatory heart piece, in that it's some sort of binary rhythm. As a drummer snare rudiments immediately stuck out to me, as the first code nearly resembles a paradiddle.
Anyway, it's possible that these codes weren't intended to be found ingame, hence the "breaking the developer's heart". But in the case that they are, they would have to relate to something rhythmic, and beyond that these two individual rhythms need to somehow correspond to the letters and numbers cube individually.
I know I haven't provided any real speculation on obtaining the codes, but these ideas are all pretty fresh to me. It'd be nice to have this game completely figured out.
Couple of thoughts and observations: This puzzle opens when you reach New Game++ mode and able to recieve Red\Cyan anaglyph glasses. Letters cube is red and Numbers cube is cyan. I think there must be some connection. For example something visible only through red and only through cyan glass which gives you idea which cube to use. And again these dots under water - when you look through different glasses you see different patterns but that's all.