Allsides Cube Wooden Puzzle

This puzzle was designed to meet a challenge to design a 4x4x4 cube where none of the pieces could fit into a regular box smaller than 4x4x4.  In other words, no piece can fit into a 4x4x3 box.  Each of the four pieces then has a surface on part of all six faces of the cube.  In addition, there are four sliding moves required before the first piece can even be removed.  This puzzle is very difficult to put back together!