Using the data storage type defined on this page for raster images, and the draw_line function defined in this one, draw a quadratic bezier curve
(definition on Wikipedia).

   fcn qBezier(p0x,p0y, p1x,p1y, p2x,p2y, rgb, numPts=500){
      numPts.pump(Void,'wrap(t){ // B(t)
      	 t=t.toFloat()/numPts; t1:=(1.0 - t);
	 a:=t1*t1; b:=t*t1*2; c:=t*t;
	 x:=a*p0x + b*p1x + c*p2x + 0.5;
	 y:=a*p0y + b*p1y + c*p2y + 0.5;
	 __sSet(rgb,x,y);
      });
   }