The term 'CUBE' (3-D puzzle) is often associated with the 4-letter word 'SOMA'. A SOMA CUBE is a 3-D puzzle consisting of seven different pieces made up of unit cubes. It was invented by the Danish mathematician and sculptor Piet Hein in 1936. The pieces can be assembled into a variety of shapes, including a CUBE. The challenge of the puzzle is to assemble the pieces into a CUBE without leaving any gaps. The SOMA CUBE has become a popular puzzle among mathematicians, puzzlers, and game enthusiasts.