An anonymous reader sends in a mathematical puzzle introduced at the recent Gathering 4 Gardner, a convention of mathematicians, magicians, and puzzle enthusiasts held biannually in Atlanta. The Tuesday Birthday Problem is simply stated, but tends to mislead both intuitive and mathematically informed guesses. "I have two children, one of whom is a boy born on a Tuesday. What's the probability that my other child is a boy?" The submitter adds, "Believe it or not, the Tuesday thing is relevant. Well, sort of. It's ambiguous."

sciencehabit sends this snip from Science Magazine, with included video: "Researchers have created flat sheets of composite material that can fold themselves into toy boats, tents, and even paper airplanes. Based on the ancient art of origami, the sheets are edged by foil actuators — thin, solid-state motors — that contract or expand when they receive an electric current from flexible electronic circuits embedded in the sheets. After they achieve their preprogrammed shape, the sheets are held in place by tiny magnets on the edges of the fold joints. Researchers say the technology could be scaled up to create ultra-portable tripods or even cups that automatically adjust to the size of liquid being poured into them."