Solution: Long Cube

Cluefill

We start with 80 normal crossword clues. A few of them are mysterious. Noting that "Every answer has this length" must resolve to FOUR helps fill the non-mystery clues in:

Gridfill

The "Across/Down" heading and the wording of a couple clues (e.g. "each complete grid") imply that we need to put these answers into crossword grids somehow.

We can note that there are 20 clues numbered #1 and 10 clues numbered from #2 to #7. If we split these into 10 groups evenly, we have 2 clues numbered #1 and 1 clue each numbered from #2 to #7. These fit the numberings of a diagramless 4x4 mini-crossword grid, with 4 across clues (1 and 5-7) and 4 down clues (1-4).

(This also fits with the AREA clue, which tells us that there are half as many letters (160) on the outside of the long cube as there are letters in total (320), implying that each letter is checked.)

With that, we can construct 10 4x4 grids. Noticing that LONG and CUBE fall out naturally from some of them helps ID LONG and CUBE as the answers to the mystery clues, if we haven't jumped to that conclusion already. Two mystery clues indicate to shade every occurrence of the eight letters in LONG CUBE.

Net-making

The next step is to make the long cube from the 10 4x4 grids. The AREA and FACE clues imply that we don’t have to overlap our grids to make the long cube, so the long cube has dimensions 4x4x8 (in other words, 1x1x2 in units of full 4x4 grids), and we need to build its net by putting the grids adjacent to each other.

This understanding helps clarify what the second section's diagram refers to: the squares are our 4x4 grids, and something will pop out in the highlighted space if we put the squares next to each other in the right way. A little trial-and-error experimentation shows that it is possible to reproduce a given 4-letter sequence across two faces in one of the middle rows.

We can use this to guide our placement of the 10 grids so that each 4-letter sequence appears once across a middle row to "tape" a different pair of adjacent faces. Rotation is allowed since there won't be a concept of maintaining the same rotational orientation once the 3D long cube is folded up, but flipping the grids isn't since that would produce a perfectly valid grid with an alternate numbering that isn't the one given in the puzzle. This gives us the following net:

When fully assembled, the long cube looks like this:

Extraction

The final section of diagrams tells us how to view the long cube from 6 angles using the diagrams' letters, which only appear in their relative positions on certain faces of the long cube. (The three diagrams with arrows indicate that the long cube should be rotated along one long end, from one short end being visible to the other short end being visible.)

When viewed from these angles, large letters are formed from the shaded letters on the long cube's surface. This is easier to do with a 3D model but is still possible to visualize in a spreadsheet.

Intended View(s)	Letter(s)
	RA
	TT
	L (circled by the oval)
	ES
	nA (N is lowercase)
	ke (both lowercase)

Reading the letters in the given order of the 6 diagrams gives the answer, long reptile RATTLESNAKE.

Authors' Notes

The idea for this puzzle came from this CMU hunt puzzle, where we were given 10 grids in the same configuration as a net for the rectangular prism long cube used here. We noticed it was a proper net, so we cut it out and highlighted certain words. This was not the right thing to do. We stared and rotated the long cube for hours anyway. Eventually we started muttering "long cube" to ourselves. We hope this feeling was replicated in your solve of this puzzle.

Besides the diagramless aha and discovering the joys of LONG CUBE, there's not much of a gimmick to this puzzle since it mostly comes down to following instructions. There's also an unfortunate mechanic overlap with other grid fill and letter shading puzzles in this hunt. However, considering it was written in crunch time for a slot that was getting continually replaced, I'm okay with how it turned out.