Questions 12 and 13

12.
import javax.swing.JFrame;
import java.awt.*;
public class Triangle extends JFrame
{
public void paint(Graphics g) //paint class
    {
        super.paint(g);
        Polygon triangle = new Polygon(); //instantiating triangle object
        triangle.addPoint(0,0); //adding 3 points
        triangle.addPoint(300,200);
        triangle.addPoint(600,0);
        g.setColor(Color.BLUE);
        g.drawPolygon(triangle);
        lines(g);
    }
    public static void lines(Graphics g) //method for drawing lines inside triangle
    {
        for(int i=1;i<=20;i++)
        {
            g.drawLine(i*15,i*10,600-(i*15),i*10);
    }
}
public static void main(String [] args)
    {
        Triangle app = new Triangle();
        app.setSize(600,200); //the frame might block some of the drawing
        app.setBackground(Color.YELLOW); //sets background color to yellow (doesn't show up though for some reason)
        app.setVisible(true);
    }
}

13.
import javax.swing.JFrame;
import java.awt.*;
public class Spiral extends JFrame
{
public void paint(Graphics g) //paint class
{
    super.paint(g);
    spiralMethod(g);
}
public static void spiralMethod(Graphics g) //method for drawing spiral
{
    for(int i=0;i<8;i++) //for loop to make the spiral
    {
        g.drawLine(i*10,i*10+10,160-10*i,i*10+10);
        g.drawLine(160-10*i,i*10+10,160-10*i,160-10*i);
        g.drawLine(160-10*i,160-10*i,i*10+10,160-10*i);
        g.drawLine(i*10+10,160-10*i,i*10+10,i*10+20);
}
}
public static void main(String [] args)
{
    Spiral app = new Spiral();
    app.setSize(170,170); //size of frame
    app.setVisible(true);
}
}