The Klein Bottle is a 4D mathematical oddity. We test a 3D model to see how its non-orientable surface behaves when filled with liquid. Explore topology and why this shape has no 'inside' or 'outside' ...

Ever since I became interested in math, I’ve always wanted a Klein bottle. It therefore comes as no surprise that ever since receiving one, I’ve been completely enthralled with it. I stare at it every ...

Looking for a cool gift for someone mathematically inclined? An unusual, conversation-generating token of appreciation? The World Wide Web offers a number of intriguing possibilities–if you know where ...