Using a thin glass sphere with inside radius of 1, the magician made
an ice with a shape of regular tetrahedron appear inside the closed
glass (no opening or hole) where all its vertices touches the sphere.
And then thaw it with a blow torch.When the ice is all melted he makes
another similar ice tetrahedron appear inside. How many times can he
perform the trick on that same spherical glass without breaking it?
!
*