We start with a positively curved arc (the red curve). |
It is moved by the motion generated by letting the blue circle with radius 1 roll inside of the black circle with radius 2. |
We then determine the (green and cyan) envelope of the red family of curves. This is the outer part of the design |
We now move the green curve around by the opposite motion. |
The missing inner part of the design is determined as the envelope of the green family of curves. |
The final design. |