One well-known symbol of the philosophy of duality known as yin and yang is the taijitu.



Task

   Create a function that, given a parameter representing size, generates such a symbol scaled to the requested size.
   Generate and display the symbol for two different (small) sizes.


unitsize(1 inch);
 
fill(scale(6)*unitsquare, invisible);
 
picture yinyang(pair center, real radius) {
    picture p;
    fill(p, unitcircle, white);
    fill(p, arc(0, S, N) -- cycle, black);
    fill(p, circle(N/2, 1/2), white);
    fill(p, circle(S/2, 1/2), black);
    fill(p, circle(N/2, 1/5), black);
    fill(p, circle(S/2, 1/5), white);
    draw(p, unitcircle, linewidth((1/32) * inch) + gray(0.5));
    return shift(center) * scale(radius) * p;
}
 
add(yinyang((1 + 1/4, 4 + 3/4), 1));
add(yinyang((3 + 3/4, 2 + 1/4), 2));