A puzzle
A parallelepiped with edges 3,4,7, that can be divided in six equal pieces with three strata of 1,4,9 little cubes: a non-verbal proof of the fact that the sum of the squares of the first n integers is n(n+1)(2n+1)/6.
© matematita
The image belongs to the sections...:
Numbers (Numbers)
Puzzles involving reconstruction of polyhedra (3D geometry)
