Katie has a PhD in maths, specializing in the intersection of dynamical systems and number theory. She reports on topics from maths and history to society and animals. Katie has a PhD in maths, ...

Twenty-five years too late to help Ross get his new couch into his apartment in "Friends," a mathematician has finally solved the pesky "sofa problem." The math problem delineates the largest-size ...

Most of us have struggled with the mathematical puzzle known as the "moving sofa problem." It poses a deceptively simple question: What is the largest sofa that can pivot around an L-shaped hallway ...

In a scene from the classic sitcom, "Friends," the characters Ross, Rachel and Chandler struggle to heft a new couch up the stairs of their apartment building. As they try to get the sofa around the ...