A little amusment on an idea of [url=https://fr.wikipedia.org/wiki/Victor_Vasarely]Victor Vasarely[/url], father of Op' Art. This is an elaboration on [url=http://tube.geogebra.org/material/simple/id/115246]Patrick Clément[/url] book.
You can change the point controlling the cicle, the radius, the style and size of points and their numbers.