Evil Twin 4x4

For build instructions and an overall review, check out my video on the puzzle: https://www.youtube.com/watch?v=HpSL6P8Kh2c

The Evil Twin 4x4 is a puzzle that appears to be a 4x4 Rubik's Cube, but is actually made by fusing two 3x3 puzzles at a 2x2 corner block, and then adding extra cubies to give the appearance of a 4x4. The first puzzle of this type was made by a Twisty Puzzles forum member in 2007. The example in the video was made by fusing and extending 30mm 3x3s with 3D-printed extensi