I tried to create an adjustable Bézier curve with the following simple code. However the curve didn't show up. What is the problem? Please help.
pts = {{0, 0}, {1, 2}, {2, 0}, {3, 3}};
bez = BezierFunction[pts ];
Manipulate[
Show[Graphics[{Red, Point[lo], Green, Line[lo]}, Axes -> True],
ParametricPlot[bez[lo ], {t, 0, 1}], ImageSize -> { 200, 200 }],
{{lo, pts}, Locator}
]