Have you ever tried to do a brainteaser in which you have to connect the dots to make the outline of a house in one continuous stroke without going back over your lines? Or perhaps you've clicked on ...

Have you ever tried to do the brainteaser below, where you have to connect the dots to make the outline of a house in one continuous stroke without going back over your lines? Or perhaps you've ...

A theorem for coloring a large class of “perfect” mathematical networks could ease the way for a long-sought general coloring proof. Four years ago, the mathematician Maria Chudnovsky faced an all-too ...