When all of the split edges of the WitEden 4x4x4 Mixup Edge-rebuilt Cube (Black) are properly oriented along the equator, they can separate. If you choose not to use the additional setup/scramble option, it can remain a standard 4x4 Mixup puzzle. However, by doing so, this hidden edge mechanism introduces an additional level of complexity. Fans of deep-cut and shape-shifting puzzles will find this challenging task mind-bending.