/*  Draw Taijitu, AKA yin-yang circles  */
/*  For Maxima 4.7 and later  */

draw2d(
    border=false, nticks=200,
    fill_color=black, ellipse(0, 0, 2.05, 2.05, 0, 360),
/*  ellipse(,,,,x,y):  start position, size of slice (degrees)  */
    fill_color=white, ellipse(0, 0, 2, 2, 270, 180),
/*  Circle() and Disk() done in first black shape  */
    fill_color=white, ellipse(0, 1, 1, 1, 0, 360),
    fill_color=black, ellipse(0, -1, 1, 1, 0, 360),
    fill_color=white, ellipse(0, -1, 0.25, 0.25, 0, 360),
    fill_color=black, ellipse(0, 1, 0.25, 0.25, 0, 360)
    );