the 'corner' balls of the cannonball tetrahedron can be considered the vertices of a tetrahedron with edges of length 2d.
the height of that tetrahedron is then 2/3 x sqrt6 x d.
the height of the cannonball stack adds two radius lengths to that number.
then: (2/3 x sqrt6 x d) + d
Posted by rixar
on 2004-08-03 21:17:38