Applet rysujący trójkąt na podstawie kliknięć użytkownika.

import java.applet.Applet;
import java.awt.Color;
import java.awt.Event;
import java.awt.Graphics;

public class Trojkat extends Applet 
{
    int xpoint;
    int ypoint;
    int xstart;
    int ystart;
    int i=0;
	
    public void init()
	{
		setBackground(Color.BLACK);
	}

    public boolean mouseDown(Event e, int x, int y) 
	{
		Graphics g = getGraphics();
		if(xpoint==0&ypoint==0)
		{
			xpoint = x;
			ypoint = y;
			xstart = x;
			ystart = y;
		}
		else if(i==1)
		{
			g.setColor(Color.white);
			g.drawLine(x,y,xpoint,ypoint);
			xpoint = x;
			ypoint = y;	   
			g.setColor(Color.white);
			g.drawLine(xstart,ystart,xpoint,ypoint);
		}
		else
		{
			g.setColor(Color.white);
			g.drawLine(x,y,xpoint,ypoint);
			xpoint = x;
			ypoint = y;
			i++;
		}
		return true;
	}
}