In an ambitious effort to revive the barren wastelands, Mechanicals have begun planting experimental farms far from the safety of Org Valley. The worker bots stay busy as they manage the planting, irrigating, and harvesting of these little farms. To complicate matters, they also must build electromagnetic walls to zap the insect drones bent on ruining all living things.

Sure, this is a fun game, but we have to be honest: you will know how to add up a shape's perimeter and figure the area of a circle when you're done. You'll also become an expert at finding missing angles while learning the names of all sorts of polygons.


Perimeter Defense is a winner of the 2010 Games for Learning competition, sponsored by NYU, Microsoft, and Motorola.


  • Use your mouse to select a location and then click "Launch" to start the game.
  • During the game, select items in the right-menu bar and place them on the map.
  • Click anywhere on the map to give your fertilizer or harvester bots commands.
  • Click menu for in-game help and geometry reference.