Floppy Cube turning - i.e. an edge piece may only twist if there is at least one corner piece adjacent to it. The mass-produced version does not feature this mechanism, which allows edge pieces to twist "on their own" - causing the puzzle to be considerably easier. The four edge pieces now have 4 orientations each on the Super Floppy Cube (compared to the Floppy Cube's 2); therefore, the edges can now be orientated in 4 different ways. However, the edges still cannot be permutated. There are now 12 different locations that the four corner pieces could be located in (up from
Prince Rupert's cube by the two opposite points, as in the case of Prince Rupert's problem. If the aspect ratio is not constrained, the rectangle with the largest area that fits within a cube is the one that has two opposite edges of the cube as two of its sides, and two face diagonals as the other two sides. Alternatively, one may ask for the largest formula_4-dimensional hypercube that may be drawn within an formula_5-dimensional unit hypercube. The answer is always an algebraic number. For instance, the problem for formula_6 asks for the largest cube within a four-dimensional hypercube. After Martin Gardner posed