Ancient Greek Geometry
What can you make using only circles and straight lines? Yes, you can cut a pie into a million slices, but when you've got to make the pie yourself using only two dots as your starting point, the challenge becomes much greater. That's the basic idea behind Ancient Greek Geometry, a webtoy by Nico Disseldorp that uses basic mathematical principles to spin basic drawing into an intriguing puzzle.
Your only two tools when playing with Ancient Greek Geometry are a straightedge and a compass (the kind that looks like a giant pair of tweezers, not like a GPS's compass). Starting with two given points, you can build your design by drawing a line between two points (click and drag to connect them), or a circle that has one point as its center and another point along its circumference (click and drag to the appropriate radius). Believe it or not, you can construct a lot of shapes with these techniques, including triangles, squares, and the elusive pentagon. This webtoy gives you the choice of tackling these shape challenges within the suggested numbers of moves, or freely building your own designs. How complex you get is entirely up to you in this intriguing diversion.