I got a new chair from ikea which came with armrests. I didn't want to screw them on the chair, because I generally don't like arm-rests on my chairs and they don't fit under my desk. Not mounting the arm-rests left some blank nuts which didn't look very pretty.
3D-printer to the rescue - I printed some caps to hide the nuts
3D printed spider
3D printed elephant
little 3D figure
a happy cardboard flower