I was reminded of 'out of the box thinker' while exploring the "horse glasses" concept. it is about the opposite. Now I had written down the word "hokjesdenken" once, because I liked it. it consists of denken (to think) and hokje, little hok,i.e., a dirty place, I'd say, like a doghouse (hondenhok). - It could be a synonym of box only, when the box is dirty, unpleasant, but the link with out of the box is clear. ;-) So do you recognize this kind of metaphor in your language, meaning something like 'thinking with blinkers on', or the opposite (out of the box)?