C#

int i = 0;
while (true) {
i = i % 3;
Pen nextPen = activePen[i];
//Do something with nextPen
i++;
}

//member of your form
private int _penIndex = -1;

private Pen GetNextPen() {
_penIndex = (_penIndex + 1) % 3;
return activePen[_penIndex];
}

public class Form1 : System.Windows.Forms.Form<br />
	{<br />
		private System.Windows.Forms.Button button1;<br />
		private bool drawline = false;<br />
		private int radius = 25;<br />
		private int green = 10;<br />
		private int red = 10;<br />
		private int blue = 10;<br />
         }<br />
<br />
<br />
private void Button_1OK__Click(object sender, System.EventArgs e)<br />
{<br />
drawline = !drawline;<br />
			Random r = new Random(100);<br />
			Int32 x = Int32.Parse(r.Next().ToString().Substring(1,2));<br />
			Int32 y = Int32.Parse(r.Next().ToString().Substring(1,3));<br />
			<br />
			if (green < 230)<br />
                green += 10;<br />
			<br />
			if (blue < 230)<br />
				blue += 10;<br />
			<br />
			if (red < 230)<br />
				red += 10;<br />
<br />
			if (drawline)<br />
			{<br />
				System.Drawing.Graphics g = this.CreateGraphics();<br />
				Point P = new Point(x,100);<br />
				Point p1 = new Point (100,y);<br />
				Color j = Color.FromArgb(red,green,blue);<br />
				Pen Pe = new Pen(j);<br />
				<br />
				g.DrawEllipse(Pe,x,x ,radius, radius);<br />
				radius += 20;<br />
			}<br />
			else<br />
			{<br />
				System.Drawing.Graphics g = this.CreateGraphics();<br />
				Point P = new Point(x,100);<br />
				Point p1 = new Point (100,y);<br />
				Color j = Color.FromArgb(red,green,blue);<br />
				Pen Pe = new Pen(j);<br />
				<br />
				g.DrawEllipse(Pe,y,y ,radius, radius);<br />
				radius += 20;<br />
				this.Refresh();<br />
			}<br />
}