V-Cube 6 to the internal mechanism, thus making the puzzle more durable. The V-Cube 6b, which has the same "pillowed" shape as the V-Cube 7, was introduced later. There are 8 corners, 48 edges and 96 centers. Any permutation of the corners is possible, including odd permutations. Seven of the corners can be independently rotated, and the orientation of the eighth depends on the other seven, giving 8!×3 combinations. There are 96 centers, consisting of four sets of 24 pieces each. Within each set there are four centers of each color. Centers from one set cannot be exchanged with those from another
Soma cube their faces, such that at least one inside corner is formed. There is one combination of three cubes that satisfies this condition, and six combinations of four cubes that satisfy this condition, of which two are mirror images of each other (see Chirality). Thus, 3 + (6 × 4) is 27, which is exactly the number of cells in a 3×3×3 cube. The Soma cube was analyzed in detail by John Horton Conway on September 1958 in Mathematical Games column in "Scientific American", and the book "Winning Ways for your Mathematical Plays" also contains a detailed analysis of the Soma