Collatz, Book and Pencil

Professor David Eisenbud on the infamous Collatz Conjecture, a simple problem that mathematicians may not be “ready” to crack. The Collatz Conjecture.


I love to browse randomly in search of A Good Book.


From sticks of graphite wrapped in string to mechanical pencils made of gold, centuries of innovation went into crafting the perfect writing utensil. How the Humble Pencil Conquered the World.