AR Tower Defence is a tangible and augmented reality version of the classic game ‘Tower Defence’. Often the biggest drawback with augmented reality installations and programs is that you need a camera and a see-through-display to experience them. With AR Tower Defence our goal was to create a richer user experience that did not forced the user to use special hardware to play the game. The gameplay builds on the classical version of TowerDefence, but in AR Tower Defence the users have the ability to builds their own special towers in LEGO®. Each tower have different properties (firing speed, precession, damage) depending on which LEGO®-bricks is being used to build them. The system recognizes the towers based on a QR Code placed on top of the tower – which our system is printing out for the users based on which bricks they have used to build their tower. The working prototype is using FLARToolKit which is an AS3 port of ARToolKit to recognize and keep track of the position of the LEGO® towers.