Pencil Sharpening (math division): Archimedes Laboratory

Demonstrating that geometry can be fun, Archimedes Laboratory is "an 'intuitive' puzzle site with fewer formulas and more visuals, which may encourage students learning this science or just constitute a platform for reflection." Math to Discover has topics like history of numbers, mathematical patterns, etc., but there are also Puzzles to Make and Puzzles to Solve sections, with a small selection of impossible object images and instructions on how to create geometrical curiosities. <http://www.archimedes-lab.org/>