
All four candidate words are six letters long, which matters here because two words of different lengths would not line up evenly once rotated and laid over each other.
Beyond the matching length, BROACH and BREACH also share the same first two letters and the same last three letters, differing only in their third letter, which means their rotated silhouettes line up closely enough to blend into one dense pattern rather than two separate, disconnected shapes.
The other pairings either repeat the exact same word, which would just double up a single pattern instead of overlapping two different ones, or mix in BROOCH, whose double O breaks that close letter-by-letter alignment with its partner word.
So BROACH and BREACH is the pairing whose shared skeleton actually produces the kind of overlapped image described.
A different angle is to first rule out any pairing that would not even make sense as a puzzle, and then check the letter shapes of what remains.
Ruling out the self-paired option on how the question is worded, and ruling out the two options that pair in a rounded, curve-heavy word, leaves BROACH and BREACH as the only sensible pairing.
Therefore, the correct answer is BROACH and BREACH.