This puzzle requires a Mini Eastsheen 2x2 as its core. There are cube-like pieces which fit snugly around the mini 2x2 (they must be glued to the 2x2). I recommend taking off one of the mini 2x2 corners to save for the last step of assembly (See Redkb's tutorial on how to make a 1x2x2 to learn how to remove one of these corners).