Welcome to The Riddler. Every week, I offer up problems related to the things we hold dear around here: math, logic and probability. There are two types: Riddler Express for those of you who want ...

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. What is a triangle? We all know that a triangle is a three-sided shape — 1, 2, 3 sides. A triangle also ...