The most famous packing problem concerns spheres. In 1611, the astronomer Johannes Kepler proposed that the densest way to ...

† School of Chemical Engineering, Anhui Key Laboratory of Controllable Chemistry Reaction & Material Chemical Engineering, Hefei University of Technology, Hefei, Anhui 230009, P. R. China ‡ College of ...

For some reason, orb or sphere-shaped UFOs keep appearing all over the world. They are usually metallic-looking and there is ...