The Berlin chairs look fairly uncomfortable: and even the book states that only after some investigation do they appear suitable as a seat. Even so, my 144-scale versions will not grace anyone’s anatomy. Here a left and right hand version placed on the book (look at the Red square…)
NANOTRAY 
ah well, I think none of the Rietveldchairs look comfortable to me, yet many people have them (my friend’s husband made the red-blue himself, sat in it quite often).The self-making and the design beats that I suppose.