Here is a 5 x 5 x 5 cube filled with numbers.
It's a 3D adaption of standard slitherlink puzzles.
You must create a solid 3D object such that the number in each sub-cube matches the number of adjacent faces.
You can assume that the surface will never touch itself except at connections.
I'm 90% sure that this has a unique solution.
It might very well be possible to remove some numbers and still have a valid solution, but since this is a new puzzle type (as far as I know) I'll give all the information.
Please let me know what you think and most importantly, have fun!