The Rubik’s Cube is one of the most popular toys in history. It
is also an example of a permutation puzzle, which have existed in
mathematics in one form or another for at least 140 years. In
hindsight, it is strange that the cube ever became so...
I sometimes like to think about what it might be like inside a
black hole. What does that even mean? Is it really “like” anything
inside a black hole? Nature keeps us from ever knowing. (Well, what
we know for sure is that nature keeps us from...