The enigma of physical and semantic distance is so beautifully presented in this example with a dog's bone.

Functional fixedness refers to the role of combination for me. The shift in thinking here is that the box is presented like "a box of pins", therefore it is bounded with other subjects. The box really feels like it has already been used. Meanwhile, the other three subjects are empty units. But we should not only fill them with meaning, but to void the function of the box.