size(0,100);
path g=scale(2)*unitcircle;
label("$a \le r \le b$");
radialshade(unitcircle^^g,yellow+evenodd,(0,0),1.0,yellow+brown,(0,0),2);
size(0,100);
path g=scale(2)*unitcircle;
label("$a \le r \le b$");
radialshade(unitcircle^^g,yellow+evenodd,(0,0),1.0,yellow+brown,(0,0),2);
::
::
::
