Not as easy as it looks. Meet the cubic trisection. twitter 
YOUTUBE fD-zIUYhHps Published Dec 7, 2013.
Cubic Trisection was first shown to George Miller by Robert Reid as part of his box of all the ways a cube could be trisected by three equal parts. George asked Oskar van Deventer to design it. Most people have a difficult time putting it together. They usually try and force the pieces to "snap" together, whereas they easily glide together when twisted along the main diagonal. post
Robert Reid has also designed a set of 10 three-piece dissections of a cube, where each cube is split into three identical pieces. These photographs show the cardboard models that he made several years ago. post
Carlo Séquin: Prototyping Dissection Puzzles with Layered Manufacturing. In this paper we discuss two kinds of puzzles: Helicoidal sectioning of some simple shapes and realizations of some burr puzzles. pdf
A burr puzzle is an interlocking puzzle consisting of notched sticks, combined to make one three-dimensional, usually symmetrical unit. wikipedia