Our heroes have travelled around the galaxy, collecting puzzle answers and strange sets of four coordinates. Each coordinate appears to have exactly one zero in it, a close reading of the stories also suggests that colours have something to do with things: the colours red, yellow, green, and blue are each mentioned in one story each day. If we compare these colours to the coordinates, we notice that the story colour predicts which coordinate will be zero: (red, yellow, green, blue). Conveniently, this also matches the visible light spectrum from long to short wavelength. The meta puzzle released on Day 5 contains five coloured truncated octahedrons and five hexagonal grids. The central colour of each solid matches the central coloured tile on each grid, and it's not a stretch to link each solid and its grid to the corresponding Day. This indicates that we need to figure out how our four coordinates for each Day link with the appropriate solid and grid. Each hexagonal face of the truncated octahedrons has been marked as positive or negative, and we can assume that the unseen hexagonal faces have the same colour and opposite polarity. These four pairs of coloured faces give us an unusual, non-orthogonal four-dimensional coordinate system in a space constructed out of these solids — which do, conveniently, fill Euclidean 3-space in a tessellation called the bitruncated cubic honeycomb. We can use the provided solids to orient ourselves in this space, and use each coordinate to find a particular position in the honeycomb. What do we do when we get there? The first thing to try is writing in the puzzle answers, and the natural direction to write them in is along the coloured axis left at zero by that coordinate (i.e. the colour of that story). The provided hexagonal grids, then, are likely two-dimensional projections of this tessellation from the same viewpoints as their corresponding solids. (In reality, each of the hexagons in this projected map would actually look like the projected viewpoints of the solids above, but the gaps between the central hexagon faces have been eliminated here for presentation.) Since we're going to project our 3D tessellations anyway, we can make things easier for ourselves by simply using these grids to fill in the puzzle answers in the first place, ignoring the depth component of each axis. The filled map for Day 1 is provided below as an example: Note that the overlapping words in this projection cross at the same letter, suggesting that we've done the right thing, and thankfully eliminating the need to check which letter was written at the closest depth. (This is true across all five maps, with the exception of one answer on Day Three which unfortunately had to be changed afterward.) Indexing into the filled letter maps using the numbers provided gives us five words: - OCEANUS
- NEARSIDE
- SWIRL
- ALBEDO
- MOON
Throwing any three or four of these words into Google leads us to |

The answer is: reinergamma |
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