Task: Yin and yang
C#:     public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            Paint += Form1_Paint;
        }

        private void Form1_Paint(object sender, PaintEventArgs e)
        {
            Graphics g = e.Graphics;
            g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;

            DrawTaijitu(g, new Point(50, 50), 200, true);
            DrawTaijitu(g, new Point(10, 10), 60, true);
        }

        private void DrawTaijitu(Graphics g, Point pt, int width, bool hasOutline)
        {
            g.FillPie(Brushes.Black, pt.X, pt.Y, width, width, 90, 180);
            g.FillPie(Brushes.White, pt.X, pt.Y, width, width, 270, 180);
            float headSize = Convert.ToSingle(width * 0.5);
            float headXPosition = Convert.ToSingle(pt.X + (width * 0.25));
            g.FillEllipse(Brushes.Black, headXPosition, Convert.ToSingle(pt.Y), headSize, headSize);
            g.FillEllipse(Brushes.White, headXPosition, Convert.ToSingle(pt.Y + (width * 0.5)), headSize, headSize);
            float headBlobSize = Convert.ToSingle(width * 0.125);
            float headBlobXPosition = Convert.ToSingle(pt.X + (width * 0.4375));
            g.FillEllipse(Brushes.White, headBlobXPosition, Convert.ToSingle(pt.Y + (width * 0.1875)), headBlobSize, headBlobSize);
            g.FillEllipse(Brushes.Black, headBlobXPosition, Convert.ToSingle(pt.Y + (width * 0.6875)), headBlobSize, headBlobSize);
            if (hasOutline) g.DrawEllipse(Pens.Black, pt.X, pt.Y, width, width);
        }
    }

Java: package org.rosettacode.yinandyang;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.image.BufferedImage;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;

public class YinYangGenerator
{
    private final int size;

    public YinYangGenerator(final int size)
    {
        this.size = size;
    }

    
    public void drawYinYang(final Graphics graphics)
    {
        
        final Color colorSave = graphics.getColor();

        graphics.setColor(Color.WHITE);
        
        graphics.fillOval(0, 0, size-1, size-1);
        
        graphics.setColor(Color.BLACK);
        
        graphics.fillArc(0, 0, size-1, size-1, 270, 180);
        graphics.fillOval(size/4, size/2, size/2, size/2);
        
        graphics.setColor(Color.WHITE);
        graphics.fillOval(size/4, 0, size/2, size/2);
        graphics.fillOval(7*size/16, 11*size/16, size/8, size/8);

        graphics.setColor(Color.BLACK);
        graphics.fillOval(7*size/16, 3*size/16, size/8, size/8);
        
        graphics.drawOval(0, 0, size-1, size-1);
        
        
        graphics.setColor(colorSave);
    }

    
    public Image createImage(final Color bg)
    {
        
        final BufferedImage image = new BufferedImage(size, size, BufferedImage.TYPE_INT_RGB);
        
        
        
        final Graphics graphics = image.getGraphics();
        
        graphics.setColor(bg);
        graphics.fillRect(0,0,size,size);
        drawYinYang(graphics);
        return image;
    }

    public static void main(final String args[])
    {
        final int size = Integer.parseInt(args[0]);
        final YinYangGenerator generator = new YinYangGenerator(size);

        final JFrame frame = new JFrame("Yin Yang Generator");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        final Image yinYang = generator.createImage(frame.getBackground());
        
        frame.add(new JLabel(new ImageIcon(yinYang)));
        frame.pack();
        frame.setVisible(true);
    }
}