Links for July 2017
Mary Katharine Goddard, printer of the Declaration of Independence and postmaster
In her boldest move, Goddard put her full name at the bottom of all the copies of the Declaration that her printing presses churned out and distributed to the colonies. It was the first copy young America would see that included the original signers’ names — and Congress commissioned her for the important job.
Solving a Rubik’s cube quickly is NP complete
In 2010, programmers found that a 3x3x3 Rubik’s cube can be solved in a maximum of 20 moves from any starting position, no matter how scrambled.
A year later, Demaine, Eisenstat and their colleagues devised a formula to solve a Rubik’s cube with sides of any length and found that the number of moves required for a cube of side n is proportional to n2/log n.
Finding the number for a cube with n=3 took several years of computing time and Demaine estimates that the n=4 case would take billions of times longer. “I conjecture it will never be fully solved,” he says.
This is the upper limit for the most scrambled cubes, but many cubes will not take that long. Figuring out whether any given configuration of a cube will take fewer moves is tricky. “We know an algorithm to solve all cubes in a reasonable amount of time,” Demaine says. “But if I give you a particular configuration of the cube, and then you want to solve it with the fewest moves for that configuration, that’s really tough.”
Cryolevitating magnet on a mobius stripSurprisingly simple tips from 20 experts about how to lose weight and keep it off by Julia Belluz
Why did Europe lose the Crusades?
Obamacare reduced medical bankruptcies
Office of Technology Assessment (OTA), 1972-1995
Doctor salaries (ave $204,000 – $443,000 by speciality)
Republicans try to kill CBO (Congressional Budget Office)
X-Rated Furniture Of Catherine The Great
Killing hypothalamus stem cells reduces lifeaspan 10%, might speed up aging
Study of indiana school voucher program finds that at best it is a waste of money and that it likely retards learning. The details are worse than the title suggests