“Help me and let me help you.” Or in Ghana’s Twi language: “Boa me na me mmoa wo.” The aphorism signifies cooperation and interdependence. And like many Twi expressions, it can be communicated with a ...

Creatively tiling a bathroom floor isn’t just a stressful task for DIY home renovators. It is also one of the hardest problems in mathematics. For centuries, experts have been studying the special ...