The question mark on the original design had been directly added to the model making it impossible for dual extruder printer to easily print in dual colors.

3d block QM.stl : include the question mark for the four sides. (to directly print on the cube /*/ dual extruder)

QM.stl : A simple question mark (to print and glue to the original model later on. /*/ Simple extruder)

Warning : I tried my best to align everything there is maybe a bit of error in the placement so just to be sure check before printing if it's aligned in your slicer.