sentences:  A subsequent challenge to this is to fit the pieces back into the 2-dimensional frame from which they came.With the presence of more than one puzzle available, pieces of several different cube puzzles can be joined together to make up larger and more complex structures other than the basic 6 faced cube.Some structures are more difficult to construct than others and the more pieces available, the easier it is to find a solution that makes a closed shape since there are more options of pieces to choose from.