6-1	Construct an animated gif file showing the formation of the cardioid.
6-2	Construct an animated gif file showing the formation of the nephroid.
6-3	Construct an animated gif file showing the formation of the deltoid.
6-4	Construct an animated gif file showing the formation of the astroid.
6-5	Construct an animated gif file showing the double generation of the cardioid.
6-6	Construct an animated gif file showing the double generation of the nephroid.
6-7	Construct an animated gif file showing the double generation of the deltoid.
6-8	Construct an animated gif file showing the double generation of the astroid.