Fit the W's into the box so that none of them stick out.
You can buy this puzzle from Creative Crafthouse:
Instead of a box, it comes with five single cubes to fill out the 4×4×5 block. It also mentions many other rectangular blocks that you can make with the pieces! Most of them are easier to solve than the original Dilemma. This was the idea of Dave Janelle, the head of Creative Crafthouse.