I found that with all my Bezier messing around, I needed some simple balance.

This thing is a simple yin/yang symbol.

You can print it as is, although to make it look good in a single color, there is some slight separation of the two halves. Still very yin/yang ish. It does NOT use any Bezier curves! Although, I'm sure you could.

Really it was an experiment in coloring with OpenScad. It turns out that OpenScad will still try to apply color to the parts that have been removed.

For this thing, it prints as two halves of the same thing, with one rotated 180 degrees around the z-axis. Of course it is parameterized, so you can print it any size you want. You just have to select the greater radius, and the radius of the 'dots'. I'm sure interesting variants can be made, but there's the basic form.