The math on that is easy. The volume of a cube is X^3, the volume of a sphere is 1/6 * pi * X^3, so the difference is a little under 1/2 X^3. Put another way,

The math on that is easy. The volume of a cube is X^3, the volume of a sphere is 1/6 * pi * X^3, so the difference is a little under 1/2 X^3. Put another way, the cube is (roughly) twice the volume of the sphere.