The power of the human mind. Both kids and adults will love twiddling with them, stretching and coiling a

The Optrix is a dual hand spinner that creates a stunning visual effect. Part 2 of challenge.

Once the payment is complete, you'll be brought back to Thingiverse. For the DIY crowd there are countless instructions for 3D printing these yourselves. The coils are connected together and are not easy to separate.