public void Serpinski (int depth, int level, int x[], int y[], int num_points){
  		if(depth == level){//base case: if the depth equals the level then draw the triangle
  			g_parent.fillPolygon(x, y, num_points);
  			g_parent.setColor(Color.GREEN);
  		}
  		else{//recursive case
  			depth++;
  			//compute center of the sides the sides
  			//centers of x co-ordinates
  			int x0 = (x[0] + x[1])/2;
  			int x1 = (x[0] + x[2])/2;
  			int x2 = (x[1] + x[2])/2;
  			//centers of y co-ordinates
  			int y0 = (y[0] + y[1])/2;
  			int y1 = (y[0] + y[2])/2;
  			int y2 = (y[1] + y[2])/2;
  		    //then create new x and y arrays with new points, and solve recursively
  			//need three recursive calls because you then divide the triangle into three more triangles
  			int[] newX0 = {x[0], x0, x1};
  			int[] newY0 = {y[0], y0, y1};
  			Serpinski(depth, level, newX0, newY0, num_points);
  			
  			int[] newX1 = {x[1], x0, x2};
  			int[] newY1 = {y[1], y0, y2};
  			Serpinski(depth, level, newX1, newY1, num_points);
  			
  			int[] newX2 = {x[2], x1, x2};
  			int[] newY2 = {y[2], y1, y2};
  			Serpinski(depth, level, newX2, newY2, num_points);
  		}
   	}