<s>[INST] The vertices of a regular octahedron are on the x, y, and z axes.
Each vertex is at a distance 'a' from the origin. The distance between two adjacent vertices is 'b'.
The coordinates of one vertex are (a, 0, 0).
Kepler guessed that the distance between two vertices might be b = √2a.

Is Kepler's guess correct?[/INST]