***** READ ME *****
A BIG THANKS TO DEVIN FROM MakeAnything for inspiring me to do this.
This is a multicolor cover printable with any single extruder printer.
1) import all the files (1-2-3-4-cover) to the slicer.
2) Allign them to the center (I used Simplify3D)
3) Print each part with a different color, without removing them from the bed.
4) As last print, print cover.stl (I suggest to start with pla filament and then swap with a flexible one).
It fits perfectly if you print with flex filament.
IF YOU USE ONLY PLA
Scale all the files up to 100,5% or 101%