PC curve of 5 points

Parametric curve for 5 user defined points .Good for understanding of the basic PC curve algorithm

Here the user can first choose whether to give a set of 5 points or display the built in plot of 5 given points . First the 5 line segments are plotted .Then a PC curve through first 3 points is plotted tangent at first and third point and passing through second point . Then another PC curve tangent at third and fifth point and passing through fourth point is plotted .These two PC curves are treated as one when they both are tangent at the third point .