# Unsolvable Rubik's cube 4x4

I am absolutely baffled by a 4x4 Rubik's cube I'm working on!

Having arrived at an almost solved puzzle bar one flipped corner, I concluded it was assembled incorrectly after reading about similar situations. (Later told by friend their kids had had it fall apart and reassemble one day)

I got to disassembly and noticed it is nothing like any of the cubes in tutorials, the corner pieces seem to be fixed to the centre ball, and not removable without disassembly of the centre ball.

I concluded the only solution was to alter the tiles on the corner piece which worked fine, and reassembled the cube in its solved state

I mixed it up then got to solving and arrived at a peculiar situation that didn't seem to match any cases the tutorial was suggesting is possible, so eventually went to an online solver and thoroughly entered my scenario several times, each time getting back an impossible solve error - cube is assembled incorrectly.

So my question is..! How is it possible that a cube that was solved, is now unsolvable regardless of how it is assembled? Surely it would be feasible to backtrack in theory and arrive solved.. I'm quite sure I haven't forced any pieces into illegal manoeuvres, no great speed or force happening.

Is there an incorrect way to assemble a solved 4x4 cube?

• What happened is a parody; one edge side's pieces have been placed the wrong way (for example the white-red edge has 2 pieces, however they have been arranged the wrong way). Taking out 2 of the same edge pieces and rearranging it should make the cube solvable. Commented Jun 24, 2023 at 1:28
• @Stevo parody or parity? Commented Jun 24, 2023 at 1:33
• How would the online solver know the difference? I did see the OLL and PLL parity situations, the one corner unsolved didn't resemble anything like them.
– Josh
Commented Jun 24, 2023 at 1:41
• puzzling.stackexchange.com/questions/87595/… I think this thread shows the same situation
– Josh
Commented Jun 24, 2023 at 1:43
• I’m voting to close this question because the problem it asks to fix is apparently not reproducible Commented Aug 29, 2023 at 22:57