Patrick Rothfuss (Kingkiller Chronicle) mentioned a similar thing in writing, I think. He'll be stuck trying to describe something and he just can't get it "rig

Patrick Rothfuss (Kingkiller Chronicle) mentioned a similar thing in writing, I think. He'll be stuck trying to describe something and he just can't get it "right", so he'll go for a walk or something and later his mind will come up with the perfect prose to insert at the part he was stuck on.