Update: Conflicting information on the Rubik's cube/Department of Homeland Security thing -- though the TM owner asserts rights in the design of the puzzle in the EU, it seems as if only the word mark "Rubik's Cube" is a registered TM in the US. I would think the design is functional, but maybe not. The deeper question, it seems to me, is not whether there is a potentially valid IP claim underlying the visit to a toy store, but why Homeland Security is visiting a toy store in the first place. Are they terrorist cubes?