A few months ago, I happened to see a receipt of payment from our PayPal account. To Hong Kong. For 150 Euros. In our family, this only could mean one of two things. The first possibility is a hacker, ...

Mathematicians and hobbyists have had a half-century of fun exploring the 43 billion billion permutations of Erno Rubik’s creation. “My method was understanding,” Erno Rubik said of the iconic twisty ...