The following code fragment makes cubicCurve at the top of Figure 52
and quadraticCurve at the bottom compatible.

TFrameBundle frameBundle( TRGBColor( 0, 0, 0 ), 5.0 );
TGCurve quadraticCurve( TGPoint( 25, 25 ),
TGPoint( 45, 100 ),
TGPoint( 95, 75 ) );
TGCurve cubicCurve( TGPoint( 25, 125 ),
TGPoint( 45, 200 ),
TGPoint( 95, 175 ),
TGPoint( 70, 150 ) );
thePort.Draw( cubicCurve, frameBundle);
thePort.Draw( quadraticCurve, frameBundle);
cubicCurve.MakeCompatible( cubicCurve, quadraticCurve );
thePort.Draw( cubicCurve, frameBundle );
thePort.Draw( quadraticCurve, frameBundle);