Ying-Yang Optical Illusion

The idea here was to create the yin-yang symbol as an application to Sugihara's optical illusion. At a 45° angle from above, you are supposed to see half of the S-cut semicircle. If the object is seen 45° from the other side, it will appear to be the S-cut semicircle has flipped. However, I noticed that Sugihara's cylindrical model won't work because, on a 2D surface, both components of yin-yang overlap too much and can't create nice curves no matter the orientation. Instead, the semicircle is on the XZ-plane while the S curve is on the XY-plane. These two segments can be made into a tube and printed.