education This delightful pond puzzle asks you to solve a geometric problem with moral undertones Ellsworth Toohey
Science Carl Sagan: How the circumference of the Earth was calculated using only sticks, eyes, feet, and brains Ruben Bolling
mathematics "Einstein Tile" mystery solved: amateur mathematician discovers unique 13-sided "hat" Mark Frauenfelder
mathematics This "Weird Units Calculator" can convert watts into T-Rex bites and lightsabers Thom Dunn