Trigonometric ruler a.k.a. Navigational Portal

You no longer need trigonometric tables or calculators for math lessons. A Trigonometric Ruler is all you need.
The package includes a clever device that is essential for the educational mode of the game starting from level 2. This trigonometric ruler also known as 'Navigational Portal'. It not only serves its purpose within the game but can also stand alone as a unique educational tool that is unmatched anywhere in the world.