A side effect of joining 4 and 5 is to wedge compartment 9 directly against their connecting corner. We have seen how this makes it possible to infer the contents of 9 from the contents of 4 and 5. It is also possible to infer this information from other sources.
At any spot on the Hypercube, we may look to the compartment directly opposite our position to find the necessary connecting point leading to 9.
In addition to 4 + 5, the union of 1 + 8, 2 + 7, and 3 + 6 will also position each pair of joined compartments directly against a different wall of the ninth compartment, the contents of which can then be inferred from sounds, temperature, and vibrations through the wall. Combining the information gained by a study of all four walls at junctions 1 and 8, 2 and 7, 3 and 6, and 4 and 5 will produce the most complete possible picture of the capstone's interior.