pencilapp.nrx file:

class pencilapp extends Applet

x =int 0 ; y =int 0

method mouseDrag(e=event,i=int,j=int) public returns boolean      -- if mouse is moved with button pressed, draw a matching line
	getGraphics.drawLine(x,y,i,j)
	x = i ; y = j
	return 1

method mouseDown(e=event,i=int,j=int) public returns boolean      -- when mouse button is pressed, record it's location
	x = i ; y = j
	return 1

method main(argv=String[]) public static                          -- if no Applet window is available, build a window frame and put this object in it
	p=pencilapp()
	f=Frame("pencil test")
	f.resize(400,300)
	f.add("Center",p)
	f.show()