If you twist something — say, spin a top or rotate a robot’s arm — and want it to return to its exact starting point, ...
Mathematicians thought that they understood how rotation works, but now a new proof has revealed a surprising twist that makes it possible to reset even a complex sequence of motion ...
The 1982 SAT infamously held a math question so tricky that even its creators didn’t include a correct answer. The botch required the rescoring of 300,000 exams, scholastic victims of the knotty coin ...